Stone, there's telephoto and there's telephoto. The usual definition of a telephoto lens is a lens a front positive lens group and a rear negative lens group. These lenses have back focus or flange-to-film distance shorter than focal length. Many of the 6/4 double Gauss lenses sold as normal lenses on 35 mm still cameras are slightly telephoto, i.e., have back focus or flange-to-film distance slightly shorter than focal length; this is why when 35 mm SLRs first became popular many were offered with 58 mm "normal" lenses. That's the Apo-Tele-Xenar too. Telephoto, but not very. According to S. F. Ray, Apo-Tele-Xenars have telephoto powers (distance from front vertex to film at infinity/focal length) around 0.92. And as you can see, Schneider claims flange-to-film distance of 327.3 mm, back focus of 312 mm. Not that telephoto.

There are telephoto lenses with back focus much shorter than focal length. The 12"/4 TTH telephoto sold for F95, F134 and F139 aerial cameras is an obscure lens that, according to the VM, just covers 4x5. I have one, sometimes use it on a 2x3 Speed Graphic. It is a fat thing, has to be mounted entirely in front of the camera's tiny front standard. It makes infinity with the front standard inside the box; I estimate its back focus as around 85 mm.

As I said, there's telephoto and there's telephoto. As others have said, there's no doubt that the 350/11 Apo-Tele-Xenar is a very good lens.