Matching the original leaded paint is tough. You could refinish the rifle completely or just try to match the receiver.
For the Tantals, I've seen a close match with duracoat semi-gloss black. Use a 9:1 instead of the suggested 12:1 (color to hardener) ratio.
For the u-folders, a lot of folks use Brownell's bake on gunkote. This seems a bit too glossy for my taste though. And it can get thick in areas if you're not super careful. Personally I dislike using aerosol.
As for the park, there are those who would argue on this next point but trust me, underneath your Polish paint is a layer of gray park. For sure. It's visible if you move your FSB/FGB/or FHG retainer.
Hope this helps. I'll have some pics up soon of the u-folder I'm re-doing. Manganese Phosphate (Park) and mol resin.
Complete nonsense....you can duplicate the Polish underfolder and Tantal factory finish down to the nuts. I did my buddies Tantal this past weekend. First thing is to Zink parkerize the weapon. Second is to apply your first coat of "AK Black Gunkote and bake. Buy the bottle type instead of the rattle can . 3rd is to apply a little thicker coat and let dry by itself before sticking back in the oven . I have seen brand new Polish issue weapons from the factory and this way of refinishing almost duplicates it 100% . By the way, all black gunkote finishes DO have lead in them . Good luck !