The coin door is the one thing I didn't feel comfortable restoring myself. I could have taken a can of spray paint to it but I didn't want to risk ruining it. As far as I know there aren't any vendors out there selling Nintendo coin door reproductions which means there is a finite number of these things out there to be had. I was lucky - mine came with the cabinet and was in pretty good shape. No major dents or scratches.
As you can see the door had started to rust in several spots and the paint was bubbling all over the place. A local custom motorcycle shop has powdercoating capabilities so had them refinish it for me (as well as the bottom marquee retainer). It came out very nice and way better than if I had attempted to do this myself.
I ordered some #6-32 carriage bolts from Quarter Arcade to secure the door to the cabinet and they fit perfectly. I had to order 2 sets though since I needed 12 for the door and they only sold them in packs of 10. I also bought a $4 lock from Home Depot which fit perfectly. Here's what it looks like installed:
I'm not sure why - maybe it was the lighting or the sweet finish on the door - but I can't seem to get a good picture of it. The door looks brand new and I couldn't be happier with the result.