Sinclair used two different Diesel pump plates. The earlier one and harder to find one had the word Diesel in red letters with grommets in the 6 mounting holes. The later and more common version had the word Diesel in larger green letters. I never saw a green version with grommets. There have been several green ones on ebay lately, possible a box of them turned up someplace? I have seen the SPS61 markings before on both the green lettered Diesel plates and on some of the Sinclair Gasoline plates.
I think the SPS stands for the maker, Southwest Porcelain Signs.
Last edited by Wes Maxwell; Sat Jul 18 2015 08:13 AM.