The photo does make it look small but is in fact a 9 inch diameter light at the chrome rim, same size as a stock Model A Ford headlight. As soon as I can ID it it will be in the cl***ifed section here on the HANB. Bob
Tilt Ray and Guide are GM brand names, but they supplied big truck manufacturers as well as vehicles in the GM line. Big truck builders usually outsourced stuff like lights and electrical components rather than making their own. The mount suggests some sort of big truck. The lights like you have were used on many different makes of big trucks.
Yes, just the one, I'm a ****er for old headlights. here is another photo I just took. Twenty and postage would take it. Bob