CMP GM/Chev Oil Pressure Gauge - Wanted

[Bruce Parker (RIP)]

I'm reconsidering my electrical gauge ( I think it's busted, U/S and NFG) and would now like to put in a mechanical one. Can anyone help me find an oil pressure gauge (in "it looks like it might work" condition or better) for an early CMP Chev or GMC (commercial type) square instrument cluster? Same gauge was used in civilian trucks of the era.

Any help appreciated.

Bruce