My little brother had an '83 D150 w/ dealer add on A/C. While the dash control looked near factory, like my '82 and '84, it was still slightly different than O.E. Underhood it was an obvious add on.

Your dash control looks to be far different that his did and while I've never seen one like that I'll say it was an aftermarket addition. IIRC, there were two major manufacturers back in the day, ARA and the other escapes me at the moment. Clardy?

Robert