I have never heard of such an animal. Sorry.

on the receipt it also says 15 rds.... im in the 3 day waiting periord.. so.. could it be the 15 round mag compared to 10rounds?

Don't know about the FXS. You can look here http://www.glock.com/g22.htm or try Glocktalk. They may know something. http://glocktalk.com/

Are you sure the FXS isn't just the first three of the serial number?

If not, perhaps it has something other than the standard plastic sights... steel sights, or...

Yes, I do not think that means anything. That seems like either a store code for something or, as stated above, a serial number thing.

There is only a Glock 19 or a Glock 19C (comped)

Ah serial number. Could be- I checked at http://glocktalk.com/showthread.php?...93#post4622205 but did not see the FXS but others close. I'd take a closer look to see.

FYI: I believe the OP already found the answer elsewhere but if anyone else needs this info:

FXS means the pistol comes w/ the full capacity mags (15 rds) instead of the old "ban" mags (10 rds).

GLOCK sellers have recently been referencing the complete part numbers for the pistols, which indicate what type of sights/mags they come w/.