Best left to a gunsmith
Proofhouse.com has sn tables for Winchester.
Search on youtube for Winchester 1300 assembly, they are internally the same.
Best left to a gunsmith.
Yes, but ejector spring may need modification- slight change in slot for spring.
Brownells gunsmithing should have a wrench that fits your Winchester model 12 end nut. this site is available on the web.
No, at least not on the original production guns (1892 - 1941).
You need to take it to a competent gunmsith
Remove the 2 screws from the end or the mag tube and the cap and spring will come out. Do so carefully as the spring is compressed
You need a good gunsmith.
Winchester Model 1200
Your rifle may be a Winchester Model 490. If so, it should have a button type safety on the side of the trigger guard to the front of the guard. This pushes through from right to left to release the safety. Please contact Winchester through their website for an owner's manual for your rifle.