Welcome to Marlin Owners and congrats on your first Marlin! 1982 was a good year, and is the last year they were manufactured without the crossbolt safety. A lot of folks prefer the pre-safetys because of the cleaner lines and one less thing to complicate operation.
It's pretty common for a 30-year-old gun to have some "character". I would suggest you go slow and not overdo restoration. A lot of mistakes are made by people wanting to 'refinish' an older gun. I like to see some wear and 'history' on an older gun. I'd suggest you sit back and listen to what people here suggest before making any decisions.
Here's my suggestions, but take them for what they are - only one person's suggestions. It is, after all, your rifle and you need to do what makes you happy.
First the stocks. I think they look pretty good. I would never recommend sanding them - it destroys the patina and doesn't look right on an older gun. The scratches can easily be toned down or even virtually erased with a coat or two of Birchwood Casey Tru-Oil. You could strip the stocks, but I wouldn't recommend it - they're fine. Remove the rear sling stud screw first and get a bullseye from this site or a place like Brownells or Midway. They come long, and it's best to cut one in half to use. Mix some 5-minute epoxy with a stain that matches the color of the wood and glue the bullseye in place. Tap it down with a light hammer and don't go below the surface of the stock. Once it hardens, sand it down close with some medium grade sandpaper on a popsicle stick. As you get close, switch to a finer grade and go slow. Try not to sand the original finish or wood, but if you do, don't sweat it. Carefully remove the buttplate and pistol-grip cap and their white spacers. Be gentle with the pistol-grip screw because they are gold plated and get brittle. If you break off part of the head you can get a replacement. Don't horse it - if it's stuck hard leave it on and work around it. Tru-Oil is really easy to use. Hang the stock to dry with a string tied to a screw replaced partway in the buttstock. You can apply it with a cloth or your finger. Some folks will recommend wipe-on poly. I'd do the whole stock rather than just the scratches, but you can also do just a touch-up. If you are going to use a sling, the stud is typically around 2.5-3 inches from the toe of the buttstock. Be very careful to center it.
The forestock is a little trickier because you'll have to remove or slide the magazine tube sling mount and rear barrel band out of the way. Get a set of gunsmithing screwdrivers. You can get a cheap set at Wal-Mart for $10. Don't use regular screwdrivers. Unscrew the rear barrel band screw and slide the barrel band forward. If the screw is stubborn you may want to rethink removing it because getting the screw back in can sometimes be a hassle. Use your judgement. Take the forestock off if you can and put a coat of Tru-Oil on it. For feel, I buff the final coat of Tru-Oil with 4-0 steel wool, vacuum it clean, and put on a coat of B-C gunstock wax. Wax just feels right on an older lever gun.
The pitted spot on the front end of the magazine tube is not uncommon. Here's what I'd do (unless you decide to completely break the gun down): Get a bottle of Birchwood Casey Blue and Rust Remover and carefully swab the spot with a saturated cotton swab. Be careful not to let the remover run down the tube, because it will strip the blue on anything it touches. Once it's cleaned down to raw metal, clean it with denatured alcohol or B-C Cleaner-Degreaser. Blow dry it to warm and swab on some B-C Super Blue or Oxpho-Blue. Be tidy with the blue and follow the directions about washing it afterwards. Saturate it in oil after the final bluing and leave oil on a piece of cloth on the blue for 24 hours. It may take a couple of coats. It you can't take the pitted look there are ways to remove the pitting.
I can't see your sights well, but it's likely that they are simply out of line. You can use a brass punch to re-center them. Your rear sight may be missing its elevator. You may even want to go back to the original front sight hood. Even if you scope the gun, I like the look of iron sights on a classic gun.
Since your hammer has a spur, I'm assuming it had a scope. There may be four holes on the top of the receiver. You can get plug screws or go to a scope. If you leave the spur on, make sure its set screw is snug.
Just my thoughts. If you decide to take it completely down, it's not hard and not a bad thing to do with an older gun. A good cleaning is a good thing to do to a gun where you don't know the history. If you decide to break it all the way down, I'd recommend Midway's DVD. You can follow it step by step.
Good luck with your first case of Marlinitis, and again, get lots of suggestions before doing anything. Oh - and learn about the half-cock safety position.