A/* p/p is an argente who is also champagne (another way to say this is a cinnamon who is also pink-eyed). They usually manifest as a light argente. The difference between this variety and "regular" argente doesn't seem very great and there is overlap so you may not necessarily know which you're dealing with. A lot of the argentes who come from fawn are actually pink-eyed cinnamons because red (from which fawn is derived) is so often chocolate or cinnamon "unerneath."
I don't know if they're standardized with the NMC, but they're not with the ECMA.
Interestingly, because b/b lightens not only the fur but also the eyes--just a smidgen--it is also possible to have a cinnamon mouse (A/* b/b) whose eyes are brown, not black. I've had a few of these over the years. Cameras seem to make them look red, but in life they're clearly not red, and clearly not black--they're brown!
I had some pink eyed cinnamons/champagne agouti/chocolate argente (A* bb pp) and they were a beautiful bright gold. They have a champagne undercoat, not dove, instead of blue tipped with gold as with normal argente, each hair is champagne tipped with gold.
Well they could be just as good I think, but I don't know.
This mouse is WNT Langlia, a cinnamon argente (A/* b/b p/p) bred by Jenny and owned by Kadee (TREK) as a pet. As you can see, she is also umbrous (gray stripe down her back), which is a huge fault, so Kadee has her as a pet only.
By comparison, here is a regular argente I bred:
There's really not that much difference in color...
Umbrous is a a dominant allele which causes a dark spine. You usually see it on sable. It also shows up on agouti-based varieties (agouti, argente, cinnamon) where it is a fault. It doesn't show up on most self varieties, and even on agouti, argente, and cinnamon it's dominance is modified by homozygosity of the A-locus (which is to say that a mouse who is A/A U/* or a/a U/* won't have a stripe or won't have as dark a stripe as one who is A/a U/*), so you don't always see it. Mice in the same litter can be umbrous and only those who are heterozygous on the A locus (A/a U/*) will show umbrous. Once it's present it's very hard to get rid of!