Can anyone tell me how many types/versions of bolts there are for the model 80 and the various Marlin deriavations and store brand models of the Mod 80. I bought a bolt for my 80 and it didn't fit. I purchased another one that did fit. The one that didn't fit has a one piece "wrap around" extractor that clips in place. Mine has individual extractors on each side of the front bolt section. I've seen new and old style used in terminology for the bolts. Which is which and are there just the two types. I want to be able to descibe it correctly. Here's a picture below. Thanks for any help.