The video I was watching happened to be talking about MP5 clones. Atlantic Firearms has/had some POF guns available (Pakistani Ordnance Factory). I don't think H&K has US production. I think it is the company that used to import the Turkish clones that is now making a US made MP5.
Anyway, if imports are restricted, certain imports that are collectible now will become more valuable. The problem is predicting which ones. I would think the best angle would be to stick with brands that have a cult following like H&K. American made versions might pop up, but the originals would still be there.
Just a thought. It is still enough of a gamble I doubt I would buy anything that I didn't sort of want anyway.
Edit: The CMP still has M1 Garands or sale. That is probably a better way to make a few dollars.