Late 80's, early 90's cam lock

Your window lock is a match for the 38-097 LH EntryGard Sash Lock. The right handed version is the 38-098. Carefully double check the dimensions to confirm that this is what you need.

Both locks are compatible with the 38-079 Casement Sash Lock Keeper.

Alternate image for 38-097

Side view of 38-097