Hi Lucky
Sure, I've heard of party suits! They were standard wear at informal outings in Vietnam. For example, here's your humble correspondent in slimmer days:
We had these things made off-base by the local 'tailors'. A party suit was a custom fitted semi-copy of a flight suit...usually made out of polyester. We would have our names embroidered on it along with the unit patch/logo. Then we would customize the suit with other sewn on patches such as 'Yankee Air Pirate', 'River Rat', or 'F*** Jane Fonda'.
I was in a F-4 night squadron, so our suit was black.
Andy