Here is another picture showing how far above the face the sight glass is. I have been unable to find any pictures anywhere of a 577-R with an internal sight glass that was towards the top of the pump. I've found many with either an external sight glass or an internal sight glass mounted just above the face. This pump was likely originally purchased fro commercial use, truck, bus, taxi, etc. I can't find any _official_ literature showing a Wayne 70 high mounted sight glass without any ad glass. I also cannot find any official literature of a 577-R with an internal, high mounted sight glass. So based on the literature I can find, I can't confirm it's either one.