Oh yeah, that helps tremendously! Just looking at it, I was wondering if the pipes were flexible enough to move around carefully. I know what you're talking about regarding the three bolts for the bracket and the 2 bolts that secure the entire assembly to the bracket.
Yeah, VERY weird. I told the (maybe newbie) parts guy the part number might-or-might-not start with "P" because I noticed the same thing. Also I think the last digits could have been either "C" or "AC" according to the eBay ad. He didn't find nuthin'.
When I talked to my bro-in-law last night he didn't seem very surprised about the cross-over. He was probably exaggerating, but said there are "only 5 or 6 brains floating around out there." (Hmmm, or did he say "manufacturers"?) I'll see if he can clarify if variety is surprisingly low.