Yes Duncan, I think they are different, but I'm not 100% sure. I think they are probably P.hongkongensis (cranial & lateral ridges). Definitely not P.caudopunctatus (Froggy - agree?). Some of the original batch had orange dorsal ridges, but this pair don't. Male has metallic streak on tail, larger cloaca. I don't know their origin, so I'm assuming they are wc.
Hmm, head in mouth sounds more like feeding than courtship behavoir. So far, mine are surprisingly peaceful and like hanging out together.