Question: Toes

Hi, I've tried to find the information here, but must be looking in the wrong place, hope someone can enlighten me!
I think I remember reading that the difference between an axolotl and a salamander larva is the amount of toes on the hind legs. Is that right? I know axies have four on the front and five on the hind, do salamanders have four on the hind legs as well as the front?
I only ask because my latest addition Paddy (wildtype colouring), still looks different (in body and head shape) to my other axies and he only has four toes on each hind leg. This may be due to these being lost before I brought him home, but it might not be. I know the only way to really tell is to wait and see if he morphs, but I'm just curious anyway.
Also I've had him for just over a month now and he doesn't seem to have grown. He's eating fine, I feed him bloodworms because being so little he struggles with earthworms and won't eat them cut up.
I recently added him to the four foot tank with Lottie and her two offspring, but they bullied Paddy and he's now in the same tank, but with a divider! He's lost quite a bit of his gill 'feathering' because of their attacks and he was a bit lacking in that department when I first got him, poor thing!
Any how, if any one has any ideas on the salamander larva thing, I'd be grateful!

With captive bred axolotls, it is not uncommon to see four toes on the rear feet in my experience. There are quite a few toe variations many owners never even notice such as bi and tridactylism,"long toes", "Short toes", and the like. Sometimes these are the result of improperly healed damage as you suspect, other times this is a result of breeding.

Back when my colony was going strong, I had a pair that commonly produced four digit rear foot offspring. Some of them actually had the fifth toe, but is was so small that it was hidden in the flesh of the foot and could only be seen by shining a bright light up from the bottom. Others had no sign of the fifth toe even when fully grown!

I would not worry too much about this unless there is visible open wounds or the like. If they are missing as a result of damage...they will grow back.