Well, after viewing every 773 on MachineTrader... I'm not sure where I stand. I want to make sure I'm comparing apples-to-apples to be fair to the seller, but I don't want to pay too much. The serial on the 773 is 519017xxx which seems to put it on the older side of the 773G series. I'm not sure if that matters or not, but it does seem to matter quite a bit on my 743.
Another oddity are the graphics. It has the "standard" looking 773 graphics, with "turbo" above the 773, like this one:
http://www.machinerytrader.com/listingsdetail/detail.aspx?OHID=10038343
But below the 773 it has "high flow". I know, according to this link:
http://www.bobcat.com/historical_specs/skid_steer/773_1999
... that the Start of Production (SOP) for the 773G was 1999 and that high flow (27gpm) seems to be "standard". There are no standard flow figures given. Of all the 2001 773's on MachineTrader, I don't think I saw a single non-773K 500K model graphics. There were lots of 773's with no year listed, so maybe one of those was a non-773K 2001.
What am I getting at? Who knows. But I am starting to suspect that maybe the 773 I'm considering isn't a 2001, but maybe a 2000. Most of the 1999 models have a totally different graphic and the rear lifting arm has a different shape to it.
There is a 773C (SOP 1994) and 773 (SOP 1997), but I know this is a 773G, so it can't be as old as 1994.