Garner's Modern English Usage covers "perquisite" in order to call out confusion between that word and "prerequisite", but notes in passing that perquisite is "often shortened to perk". No mention of "perq" which, as with other posters, I've personally never seen.

In general, if you chose a usage that generates discussion about your language choices, and there was another option that would convey the exact same thing and not generate discussion, it's best to regard that as a mistake.