Yes they did.
First time, it would have been about 1966, I had nothing to do with it but out of interest and to take the opportunity of a ride on the back of a older apprentices (or he might have just been out of his time) Velo. He had made the arrangements to take it to the works, set off very early, can't remember what time we got there but it would have been not long after 9:30 I would guess. Dropped the bike at a doorway with some kind of counter inside. Wandered around (not the works but outside) went back at the arranged hour and rode home.
Next time a year to eighteen months later, I made arrangements, by letter I presume because we did not have a phone. Went down with a pal on train/bus and waited while they did it. It would have not taken long because the frame was completely bare except for the swinging arm. I cannot remember how much it cost but it must have been fairly cheap, I was doing my work, apprenticeship and a evening/weekend job in a truck body builders to fund my biking passion, but still not a lot of money to spend.
Oddly enough I am still just as daft, going all over the place after odds and sods for bikes. Recently went to Imola where they had a autojumble type event for bikes, to wander around the circuit after spares for old MotoGuzzi, most people would think it strange, seems ok to do it for a holiday to me, beats sitting on a beach.
JohnT
JohnT