Photos of Weston XM-1?

I'm trying to ID an invercone attachment that I think goes to a Weston XM-1. But I don't personally have an XM-1 so I can't be sure.

Does anyone have a photo of the XM-1's rear (selenium cell) side? Do you know if it came (or accepted) an accessory invercone? If so, does anyone have a photo?

Many thanks in advance.
-James