Need help with condenser/date

Unitary Products Group, Norman OK

S/N WELM031393 & WELM031391


May be out of the ball park but off the top of my head E= May L= 81 or 02

I am thinking Unitary is a York product

Thanks Charlie, House was built in 1989
Never saw one of these before and now I’ve seen two!!!
No labels on the covers at all just on the serial tag.