I don't think you'll find a "factory" installation of a PTO in an AD truck. Both the PTO and bed were after-market as far as I know. So the original location will vary with whoever installed the bed and PTO.

Am I right or Amarillo?

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.