There is also a GE version of those fixtures.....Rych has one himself! I forgot the model but it starts with "GE Form" something...are you sure this is a PEMCO and not a GE?
This is a PEMCO. By the way, the GE one is the Form 205IB. The OV-10 powerpack was actually called the OV-10 I.B. I think I.B. stands for Integral Ballast. It was in Joe Maurath's OV10 that he sent me pics of.