Is it real? I do not know. I do know that I have a Sinclair HC that is about the same size, has a screw hole in the bottom center and the top has a rolled over edge like the one in question. I feel mine in 100% old and original and was used on a pump. I do not know what model pump but if they made them like this for Sinclair, I feel other brands like it could have been made too. Looks ok to me

US Air Force Retired, 1981-2007