Woog, A bit of further searching in
GMpartswiki turned up that part# listed in the
1967 Chevrolet Radio Parts Catalog on
page 32 - see screenshot below.
The radio application list on the left side of that page shows 112, 129, 141 (TILT). Those application #s are for the 1964, 1965 and 1966 model year trucks. If nothing else, it may help find a donor vehicle/source somewhere.
