Can mexican salamander regenerate any organ?
I'm going to assume you meant Ambystoma mexicanum also known as the axolotl. There are other kinds of salamanders that live in Mexico, but the axolotl is widely-studied and sometimes called the 'mexican salamander'.

The axolotl has exceptional regenerative powers, and although I suspect this ability is shared among salamander larvae(even if not the adults) there's not much research into phylogenetic distribution of regenerative capability. So in the absence of a more refined answer I'm going to hope axolotl results generalize to other salamanders.

Axolotls, as long as they don't die, can regenerate nearly any part of their brain. As a rule, as long as they don't die they can regenerate from any injury. There are a couple exceptions(it's very hard to keep an axolotl alive without a heart, so that hasn't been tested) like the eye but in general they can grow back nearly anything.

The Hox gene research I've found was done explicitly on worms and frogs, but I would feel safe concluding that axolotl regeneration relied on a similar mechanism, and that therefore they have Hox genes for internal organs. I mean, they had to grow them the first time, right?