The most egregious of the three to me is the Bubbaed up rifle. Yes, in days gone there were some fine custom sporters built on military surplus rifles. But at the time it was an economical advantage to do so. Now there are plenty of excellent commercial guns to choose from. Then you have the ones that "Bubba" decided to customize in his garage shop with a hacksaw, and file. Unfortunately that still happens all to often today. At least most of it now is being done on Mosin Nagant 91-30'a that are as about abundant as bunnies on Easter. Or "add on", replacement parts for an SKS that can be taken off to restore them to original.
As far as the ground crest, not much can be done about that. As countries fell, and regimes changed political powers removed symbols of the previous times. When you think about it, it's actually part of the gun's history.
The import marks are, as you said, required. But for collectors some importers could be more discrete. Although all my milsurps are bought as shooters, and used as such they really don't bother me all that much.
Cheapshooter's rules of gun ownership #1: NEVER SELL OR TRADE ANYTHING!