That is a unique bracket. Here is my best guess. It looks like it would go on a Bennett 76, 77 two ad glass top. Bennett 300 and 500 series have knock out plugs on the top that this bracket looks like it would fit. Also Sinclair used Bennett pumps most of the time. The bracket on this 76 takes the clamp on type pricer but if it was removed it looks like your pricer would fit.
I like shoebox pumps
Re: Sinclair visible pump price sign identification
#729052 Sun May 05 201911:26 AMSun May 05 201911:26 AM