Found this on the SS 501 Abt:
"In addition to the tanks, the battalion operated a number of other tracked vehicles. The 4. Kompanie’s armored reconnaissance platoon rode in Sonderkraftfahrzeug (special purpose vehicle, abbreviated SdKfz) 251 halftracked armored personnel carriers. Also in the 4. Kompanie was a pioneer platoon with SdKfz 251/7 halftracked engineer vehicles, which differed from the personnel carriers in that supports were welded to the sides to permit carrying small assault bridges. Both versions mounted 7.92mm machineguns."
The Vehicles
also total manpower for Kampfgruppe Peiper taken from DUGDALES VOL. I, PART 4C (DECEMBER 1944) OF PANZER DIVISIONS, PANZER GRENADIER DIVISIONS, PANZER BRIGADES OF THE ARMY AND THE WAFFEN SS IN THE WEST AUTUMN 1944-FEBRUARY 1945 THEIR DETAILED AND PRECISE STRENGTHS AND ORGANIZATIONS
3./SS PANZER-PIONIER-BATAILLON 1
Motorcycle with sidecar = 2
Kettenkrad = 1
Volkswagen = 2
Light civilian type car = 1
Medium civilian type car = 2
Heavy civilian type car = 8
Light truck = 4
Medium truck = 3
Maultier = 3
SdKfz 251/1 = 5
SdKfz 251/3 = 1
SdKfz 251/7 = 7
Light machinegun = 35
8cm mortar = 2
Flamethrower = 6
Manpower = 200
I also found that in 43', there was a reorg with a waffen ss pioneer company consisting of 2 Sdkfz 251/7 but this was posted on another forum and listed no source but I would take it as fact.