Ah interesting looking exit sign. I think I've seen ones like this before with the exposed diodes, but they otherwise looked like a "regular" exit sign with a conventional body. They were probably early LED exit signs. The earliest traffic signal LED modules had the exposed LED diodes too. I can't remember for the life of me where I saw them though.

First LED traffic lights I ever saw were in providence I was 2 they were dot type than I saw 3M LED ones years latter First LED exit was the calculator, It was called They are like huge screens you would see on Calculators