Missing parts from a 1979 "moonraker" model

The only difference between the Moonraker and the 'vanilla' shuttles was the colour scheme provided on the decal sheet.
All you really need to do is to locate the same kit that was originally used (in the case of the Airfix Moonraker, this is their 1/144 Shuttle, which is still available).
I would guess that the Revell Moonraker is the Revell 1/144 Shuttle with Boosters so you can just replace the kit and transfer the decals across.

Sorry to hear that you are missing parts for your kit. I do remember having that kit when it 1st came out, but that was a LONG time ago.

Only thing I can say is, if it was not that much try looking on ebay for that kit CHEEP. Or just get the same scale space shuttle kit and use the parts from it.

Unless someone here has the parts you need.

Good Luck

Bud