This NEMA looks like it would be a merc, but it's actually MH. Looks like they decided to reuse the old refractor. It also appears to have an external slipfitter to accommodate the 2" bracket.
Can you take pics of the pole too? They make pictures look better plus it adds character....my guess since I used to live in your area, this is one of those with very cuverved arm with a clamp style mount onto a concrete pole?
The head looks older so they may have either put a 175 watt MH lamp into the MV ballast or it got reballasted...
Yep it's a concrete pole! All of the poles in this particular subdivision are. It's also possible that it's an MV fixture with an MH lamp. The color temp of the lamp is much too warm to be MV...
usually they work for a few months to a year with MH lamp before it refuses to strike any more, ive seen a few this way, and the sylvania Metalarc lamps start easiest on MV ive found
The head looks older so they may have either put a 175 watt MH lamp into the MV ballast or it got reballasted...