gee i don't know , i bought or built from kits back when they were cheap like $260+ for a rifle and $70-$100 for a kit .
the only AKs i would pay big $$$$ for are the old milled steel ones but that just me and i am spoiled to the AKMs being a $50 cold war surplus item --those are long gone and will never return.
today i think you would be better off to just buy an AK if that is what you want , there are still a few around for semi-reasonable money i think --but the low surplus prices of yesterday are long gone.
if i was going to spend a lot of money on a rifle i might get a sig carbine or a travor bullpup or other exotic IF big money is involved --otherwise i just build more ar-15s while the ar-15 parts guns glut is still around-- today is a good time to build AR-15 and an expensive time to build AKs
and as far as that non numbered lower being some kind of protection from the BATF/government knowing what you got --that is pipe dream. some web crawler is probably reporting the entire transaction. and the feds seem very interested in all the unfinished ak/ar sellers.
i figure your more likely to end up in some kind of BATF shit list if you buy a lot of 80% cause the BATF is going search /wiretap/hack all the 80% makers for the purchase orders. hell their all ready doing it--
i'm pretty sure you can still get a good deal on a AK as people bought them during the panic of last couple years now money is tight and cash still does talk--