17 digit VINs were only introduced in 1981, as a world standard. Prior to that all Capri's used an 11 digit combined Chassis/Vehicle number, your friends being GAECJR55828. Broken down this reads as follows:
G=Germany (Country of Origin), A=Cologne (Manufacturing Plant), E=Capri (Vehicle Type), C=2-Door Coupe (Body Type), J=1969 (Year of Manufacture), R=June (Month of Manufacture) followed by 55828, the unique vehicle serial number.
The other Tag is a Body Tag which identifies the vehicle again along with many of its features and accessories. I can decode that for you, but you really don't need that information for body parts.
You can do some more research and searching for parts at
Ford Capri MK1 spare parts and product data from Motomobil Cheers, Terry