Thanks IBFS. I suspect that may be the case. So the pair arrived, and I took a look. I can definitely see a good portion of the single line "U" on the bottom stamp, but can't find anything on the top stamp. It may be there, but I'm not seeing anything. I think I'll send this in for an expert opinion. Even if this is just a case of a difficult to see watermark on the top stamp, I'd like to know if it's even possible to have a pair where one stamp doesn't include the watermark, while the other does.
Matt
