It looks like printmgr has hardcoded strings such as "HP LaserJet <model>". The list of LaserJet printer models I've found are:
1010, 1012, 1015, 1150, 1300, 1320, 2015, 2550, 2605, 2820, 2830, 2340, 3015, 3020, 3030, 3050, 3052, 3055, 3090, 3092, M1005, M1120, M1319, P1505, P2010, P2014, P2014n, CM1415fnw, CP1518ni, 100 colorMFP M175w
There are some other supported printer strings:
OfficeJet Pro L7500, Officejet H470, Photosmart D5300 serires, Officejet 9100, hp business inkjet 2300, hp business inkjet 2600, hp business injet 3000.
The also look for printers with the strings CNCL, Laser, et C et c, Office, office, Photosmart.
I'm thinking of finding out what my Xerox announces itself as and then poking it over one of these strings. I'd be curious to see if that will allow me to use it to print.