Nice historic find Pierre.
Got a question for you about that Firebird head stock and stringing:
BackgroundWhen I was working at the guitar shop we had a young regular client who played in a Foo Fighters cover band and he was fanatical about playing a "Trini" guitar just like his hero, Dave Grohl

(Yeah, I know)
To that end he bought two Chinese knockoffs one in black, the other in teal blue. They looked OK cosmetically but the electronics needed replacing. Well limmee tell ya, it was no fun.
While enlarging holes for tuners, pots etc., I didn't know what I was seeing exactly but the stuff coming off the drill bit wasn't anything resembling wood! White and powdery it was. I had my doubts that it would be strong enough to support the parts, but it worked out OK in the end.
About that head stockWhen it came to stringing the guitars, I recall I had a hell of a time reaching the treble E tuner to get sufficient winds. I had to go through a couple of different brands of strings in order to get one long enough do a satisfactory job. Are you seeing the same problem or was this a design fault of those Chinese knockoffs?