Mak 90s: matching #s, polished triggers?

Giving a cash heap plus a surplus P-83 handgun today for a Mak 90. Already own three other 'AK deriv' rifles.

A friend let me try his a few months ago. The trigger was (factory) polished and really nice.

Were Mak 90s--both stamped and milled--sold in the US with matching numbers? Being produced as sporters for US regulations, they should Not have required US parts to be installed under ATF reg. 922r.
The seller said that nothing was replaced.

Are all original triggers on all 90s known to be smoother than on most AK derivatives?

Everything matches, stamped receiver, nothing x'd out.
Light, crisp trigger ( a little better than Tapcos on WASRs)--not as silky as a friend's 90 which has the milled receiver.

Curious why the front post is offset a bit to the left, headed out to possibly find out why.

"Roger" all of the previous.

Gotmine: The Tapco sight tool only did lateral adjustments on both Saiga rifles (both were "nib" in February), along with the Maddi AK after the barrels heated up after 10-20 rds.

It's a bit of a surprise that even all-matching parts result in the need for post alignment.
There was one jam (stovepipe) in sixty rds., but it was Russian ammo and the recoil spring feels weaker than both Saigas.