Did you ever see a factory oil pressure gauge ?

When I purchase my 1975 Duster, it came with lots of goodies in a box. I found a oil pressure sending unit. When I took it to NAPA, they said it was for an oil pressure gauge. I don't think I've ever seen an A body with an oil gauge. It's brand new, but I have no idea if it would work with the after market gauges at Jegs, or Summit.