Here is a dayburning Thomas And Betts Model 113 located on a residential street near Del Prado Blvd in Cape Coral, Fl. I tried to take the pictures the best I could. I was in a moving car.
No this is a DTL. I know LCEC has used black DTL's before because a lineman working on the streetlight in front of my parents house gave the old one to me. And when I bought my OVH from LCEC the guy threw in a brand new black DTL, and a Philips lamp. Why would you think it's a diagnostic DTL? Just curious. I'm pretty sure it's a regular PC.
Hmm. No I think it's just the height of the PC receptacle and the angle the pic was taken. It could be a diagnostic DTL. But I think they have the same size cover as the regular DTL's.