Anything with an MR prefix is a Remington. As far as year I dont know how their date code works, but the last Conn built Marlins were made in 2009 so thats a 2010 or 11. Remington did use some old stock barrels marked North Haven, but if it was made by Remington in Illion, Ny then it will have the MR prefix and a REP proof mark rather than a JM.
I just received my new 1895 SBL that I ordered 5 months ago. My serial number is real close to the one you looked at, mine is MR 07504B it has a barrel with the CT, markings. I went over this rifle very carefully when I opened the box and could not find nothing that jumped out at me, sights were indexed correctly, scout rail is level and centered, no buggered screw heads, stock and forearm have no gaps in the fit up. the XS sights are dead on at 50 yds with my laser bore sighter.
I really was expecting something to be wrong after reading alot of negative posts
about the new 1895's. I will be taking it to the range on Tuesday this week to try it out. I'll post my results.
The last Marlin I bought was in 1967 and I still have it.