Ack, no! Oil in a lock cylinder works temporarily but is a long term kiss of death. It attracts and traps dust which kills the lock in short order.
Locks should only ever be lubed with dry graphite. They make tiny lifetime supply tubes of it for the express purpose of lubing locks. They cost $2 or so, are mostly air, and use the air to blow a small amount of graphite dust into the lock. Flick the tube a few times with your finger, blow a couple squeezes into the key slot, insert key and work it around. It should free up easily.
Do be aware that RV door locks of that vintage and style suffered a manufacturing flaw, or at least some of them did. The defective ones were supposed to have the key inserted and withdrawn ONLY with the blade vertical, but the defective ones could have the key withdrawn with the blade horizontal, and when that was done, it could freeze up the lock permanently. Those had to be drilled out when frozen. Hopefully yours isn’t one of the defectives and the graphite lube does the trick.