its Most Likely HPS...but it could be MH as some of the other ones are...no way to tell for sure...no Nema Tag and i dont Recall it Being Lit...its a 1 KW for sure though.
I've seen 1000 watt mercury vapor streetlights on public roads and private parking lots right across the river from me and so far I've seen at least 3 Westinghouse OV-50's there.
There are 1KW fixtures in the Garden City Shopping Center in Cranston, RI. Really old finned 2-door OV50s and finned 2-door AE 327s as well as M-1000s. All of the lights (as well as the newer HPS M-400A2's and OVX) have been converted to 400w MH. I'll get pics when the weather gets warmer.
Incidentally, this isn't a Crouse, more likely a Westinghouse. A Crouse-Hinds OV-50 would have a NEMA tag and the P-cell would be located further back towards the slipfitter.