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.

Huh. I'm a native English speaker and I've never seen that word in my life. I thought it was a typo for a moment

Literally the only other time I've ever seen it spelled out was in a 11th-grade Economics class when I told the teacher that she misspelled "prerequisite" and she explained what a perk was.

There is no such word as "perq" in American English.

https://ahdictionary.com/word/search.html?q=perq

Perhaps, it is British English.

I don't think so. Garner's is an American English usage guide, and they define it (see above).

It is not.