Are you sure they need refinished? I have an old Marlin that looked to need refinished because it had some mild surface rust, all of the bluing had an orange tint. I rubbed on a little bit of solvent on the outside, and it all came right off. Before I did this, I tried oil and it did not work. But after I used the solvent, I put on a coat of wax and then oiled it. Then wiped off the excess oil. Now it looks like a new gun. I do this same procedure to all of my guns looking like they need reblued, and this works everytime. I haven't done it to a gun in very bad shape though. And if you need parts, numrich probably has what you need.
You're wanting to use it for home defense? That's fine probably, but why the rail system? What is your reason? I personally don't understand why people feel the need to add a bunch of rails. If you want to add a flashlight or a laser, neither I agree with, then you just use the kind that uses a barrel clamp mount. If you have to, then you can use a short barrel clamp style mount rail. I'd rather just leave it alone. And if you're wanting better sights, nothing wrong with a brass bead that it probably already has. You're just going to be doing close range stuff since it's for home defense. Why cut the barrel? How long is it? What choke does it have. You will loose it if you cut the barrel.
It sounds to me you are a little new to guns. If you are, then I suggest buying a 100 round box of cheap ammo and going to the range. Get comfortable and familiar with your gun. And then buy at least 20-40 rounds of what you plan on using for home defense and go to the range. The gun I use has bigger chokes, cant remember what they are, and I use Federal 000. Fortunately I've never had to use it. If you want something smaller, I wouldn't use anything smaller than 4 shot. What size chamber is your gun? Since it's an older gun, I'd only use lead shot.
