Dan : If for some reason you have the "earlier" Hang-On (first picture attached), it would not have the spacer (which is really noted as a "Brace"). If you have a 1966 unit, it should definitely have it. If you have a true 1965 unit, I'm not sure. The reason I say this, is that even though the Illustration from the 1960-68 MPC shows the Brace (19C604) as supplied in the A/C Kit only, that number does not show up in the Text Sections of the 1960-68 MPC, the 1965-72 MPC, nor the 1966 MPC. It does, however, show up in the 1966 Electrical Assembly Manual as "C6ZA-19C761-A"(this number did not show up in any of the MPC's, nor in any of the OSI books that I have). This says one of two things to me; either it was not part of the 1965 Kit, or it had a "C5" part number. Hopefully, someone with a 1965 Electrical Assembly Manual can confirm one or the other.
Hope this helps a t least some.
Bob