The Puma is in Armoured Assault, I don't have one to hand at the mo.
Not sure on the Panzer III N, is the short barreled 75mm gun the L24? If so the gun stats are in the AfriKa OOB, actually on a Stug or Panzer IV but the stats are there in the end table. Did the armour change much in the later panzer III's, if not you could use the stats from the J, again the the Afrika OOB. Keep the cost the same as the armours the big difference really and just change the gun.