Leica is one of the few companies to actually incorporate the word "Tele" into the name of the lens to denote that it is a "TelePhoto" design. The Elmarit became the "Tele-Elmarit", the Elmar became the "Tele-Elmar" with the change of the optical formula. Tele-Photo lenses have a positive front group and negative rear group. Looking at Neblette, 1973, the 135mm lenses shown for 35mm cameras look to be telephoto designs.
Comparing lenses side-by-side, the 13.5cm F4.5 Hektor-M is about the same length as the Komura 200mm F4.5 in LTM. It is much longer than the Nikkor 13.5/3.5, Canon Serenar 135/4, Canon 135/3.5, Schacht Travenar 135/3.5, and Arco 135/3.8 Tele-Colinar (all in LTM). Last one was easy to figure out... Most of the non-Leica lenses were "about" the same length, except of course the 200/4.5. I need to do a mug shot of 135's.
I suspect the Canon Serenar 100/4 is an Anastigmat. It is a Triplet.