That is not anywhere near the original paint,that original collectors seek.
The missing ID tag in back is a HUGE factor for those same collectors too.
It might be an original model #97,(wall mount),that someone turned into a model #98,(floor mount) instead.The missing ID tag would've shown that & might be why it was removed.
Does it work properly when you hook air up to it & calibrated correctly?

Collecting Vintage Sunoco