Most of these NO-NOX signs have one hole at the top, bottom and sides. Is there a legit version with two holes at the bottom like this picture?

I owned one with one hole in the bottom. I am not aware of this sign being reproduced. It seems there are production anomalies at times. I have an original Texaco Sky Chief Petrox Pump Plate that was produced without the date at the bottom. The reason for the two holes is still a mystery.

Photo of my sign referred to above.

Thanks Stephen for posting your version of this sign. The fonts and the coloring of the two signs are the same. The only difference is the extra hole at the bottom. Does anyone else have this two-hole-at-the-bottom sign?

...the lettering is slightly - VERY slightly - different...both signs are legit; at some point they were made with different mounting hole locations...

...both versions are quite common...I didn't know about the difference for years, until I noticed it when looking at a sign that was chipped around the bottom mounting holes...

Thanks so much! I appreciate all of the expertise.