Owner is 3rd owner and says it was rebuilt at 80k; has 120k now. Is it possible to run a compression test with a normal compression gauge? First rotary.... I understand when a car is "not running on all cylinders", just want to make sure all rotors are good.

Car is VERY clean btw. Immaculate almost. So I'm pretty good on it...

 

Dave-
Nope - requires gauge specific to rotaries. May be worth dropping $100 at a Dealer to get this done right, considering the cost of a rebuild.
Few other things to watch:
-hard starts on a cold engine (sellers may get around this by "pre-warming" the engine - that is: run it - prior to your arrival.) With a full choke a cold rotary should pretty well light up instantly, long cranks followed by a rough-idle start could suggest water-jacket leak in to combustion chambers overnight, indicating failure. These engines can run fine, ONCE you get them going, but the clock is ticking...
-oil in the rad coolant. Again a sign the barrier btw the cooling system & the combustion has begun to fail.
-white smoke at start (again, these tend to be COLD starts) - indicating coolant/moisture in combustion chambers burning off at the start. liquid collecting at the tailpipe might be coolant, which is a sweet smell...
Best of Luck - great cars as any incredibly biased Forum member will attest! Lots of stories here of long-lived engines, so I hope this doesn't put you off.
Welcome-
Stu Aull
80GS

 

Crank was not long, but was not quick. Once it cranked it idled fine. Car was completely cold. No smoke. The car has sat for weeks w/o battery hooked up, because it was shipped down to Florida.

I'll have to look at an inspection. Thanks for the info.