As an ex-BA apprentice on 707/VC10/Concorde, we had a Comet to learn on! We also had Viper engines from Jet Provosts to learn about compressor balancing and tail booms from Vampires for control cable rigging - and that also applied to avionics guys!. It really doesn't matter too much what the airframe is if it's for learning basics.
..and before the Comet arrived (1969?) we had an Argonault. Even performed ERUs on it.