I've been offered a non-import mark 1983 Soviet Makarov that's in excellent condition for $1650. Looking through completed Gunbroker auctions I could only find one similar listing for a 1976 one that sold for $1970. Does that seem like the going rate for non-import marked Russians these days?

There can't be very many in the states w/o import marks.  It will really come down to what the market will bear.  I paid around $600 for a Russian '76 with some fairly discrete import marks a year ago.

I just can't wrap my head around paying that much for what should only be a couple hundred dollar gun tops, import marked or not. YMMV

It's all about what the market will bear. Most of us remember when 1891 Mosins and 1895 revolvers could be had for significantly less than a hundred bucks. Maks have been coming in less frequently, import marks have generally gotten bigger and uglier.
The Russian mil pistols have always had the most value. The largest numbers came mixed in with some Bulgarian batches and were even marked as Bulgarians by the importer.

A non-import marked Russian pistol is the top of the collector food chain in the US.

Hey if you have the means and it makes you happy go for it.   For me its hard to justify that kinda coin on a surplus gun that the east bloc made shit tons of.  YMMV.  I hope the OP scores a deal on his and enjoys it as part of his collection.  I can't lie I'd love to add a legit military Russian to my 9x18 collection but only if its a killer deal which I never seem lucky enough to come across.  I'd totally be ok with a mismarked import sneak as well.  In addition to Bulgaria I've also seen them mismarked as E German but as usual the seller knew what they had and priced em accordingly. One day maybe I'll get lucky and find one for a decent deal.

I remember the days of the crates full of $69 Mosins along with all the other cheap former East bloc surplus stuff. I also remember the import marks were way more discreet back then as well.  I wish I had bought more back then, oh well.

Yeah, I ended up getting the gun for $1250, which is about where I would expect them to be and saw them sell for several years ago. I guess a few Cuban cigars as an enticement gift worked! Lol. I have a Bulgarian sneak Soviet Mak as well in my collection, but my goal was to get one from every country and the unmarked one was going to be the “crown jewel” of it.

It was more for collecting and investing. Like I told my brother when I was helping him buy a SPAS-12 and he was wondering if the $2000 price was worth it; “it may take a little longer to recoup your money, but the price is always going to go up on them.” That was less than a year ago and I’ve already seen them sell for more than that.