[LT7A]

Glad to hear you're still working on this rig. Sounds like maybe you're going to be doing new body work and paint. But if you were still thinking about stripping the flat black back to the original paint, I was going to recommend that you try mineral spirits on the black. And if that doesn't work then lacquer thinner might help you remove it. If you're going to sand it I would start with something much less aggressive. 1500 would be a good place to start but probably would be slow going. 1000 grit is sometimes is too aggressive and removes paint to quickly so you might find the right grit somewhere in between the two.