Sam1911: A very astute Mod at AKfiles explains, along with some others, that 922r was written for importers of AKs etc, because they assemble guns from parts kits, or change parts.
There have been no known federal prosecutions for changing the weird butt stock in a thumbhole MAK 90, or using a larger mag etc in those or original Saiga rifles etc. Or changing 3-4 parts.
The ATF has added On a charge for certain changes----but when added onto an Actual felony.
If somebody has been prosecuted Only for 922r, then any documented info will be strange news.
The ATF's language is vague. The person who assembles is considered to be the importer, with nothing addressing the "end users" etc-customers.
They certainly have no interest in, nor overworked staff to research whether Billy Bob's Chinese SKS originally had a little spike bayonet.