I use acetone to remove lettering/numbers from zinc and brass models. Don't use it on plastic.
I have never had it affect the paint underneath, but a hidden test spot is always advisable. I have done several projects on the Samhongsa Williams Pacific (and Mike) like yours. Good model; great-looking proportions, though more a USRA Heavy 4-6-2 than a light USRA one.
You do not need to strip and repaint the entire model. Gosh, no. You do want to spray the parts you want to paint with a basic hardware store flat gray primer - BUT, you do not need to repaint it at all, if you want it black. Remove the lettering and re-decal it. Solvaset then Dullcote.
I painted the shiny wheels on mine; I have used (brushed) both enamel and good-quality acrylic. It will tend to chip off some, but over time it seems to get tougher. Easy touch-up.
If I can find that photo....
Found it. Kind of dark. I painted mine all over in a weathered black (really automotive dark gray primer) and detailed it for the Mobile and Ohio, which had USRA Pacifics, too. This also has TMCC/Sound, but was done so long ago that it's a Train America Studios unit.
Keep at it. I want to see it properly decorated for the L&N.
