Brew is right, mine's a "T" model.
SR9, basic post ban '91, no muzzle device, butthole stock, rounded front foregrip which won't take the bipod, welded bayonet receptacle, all had polygonal barrels, while only some '91s had poly barrels.
SR9T was the same base rifle, but somehow classified as "sporting/target," so it got an MSG90 stock and PSG1 grip and trigger. Supposedly selected for "true" actions/barrels. Can't remember what I paid, but I got a deal on it a long time ago.
SR9TC was same as the "T" except PSG1 stock.
Pros-
It's an HK.
Mags are WAY cheap now, well under $20 compared to $40 and up just a few years ago.
The goofy foregrip swaps out for any of the '91 foregrips.
US parts are available, so you can get the parts count up to put a pistol grip and conventional buttstock.
Poly barrel is very easy to clean and is supposed to be very accurate. Mine shoots about 1/2" with handloads.
Finish is one of the toughest.
Very reliable.
Assuming US parts count is sufficient, you could turn a stock SR9 into a "T" or "TC" with the proper parts.
Cons-
Expensive for a post ban.
Tears up brass pretty good if you don't spend $$ for a brass deflector.
Proprietary scope mounts are expensive.
Heavy.
Difficult to clean thoroughly.
Non PSG1 triggers are not very good.
No bolt hold open after last shot.
Some don't like the ergonomics.
I love mine, but it's a precision rifle, not a battle rifle, although the 91 is a very capable battle rifle, mine is heavy and target equipped.
I don't think HK makes them any more, they don't even list accessories for the 91 series in my most recent catalog.
THEY ARE CERTAINLY NOT IMPOPRTED AT THIS TIME even if they are being made.