I know nothing about cymbals or cymbal companies... but Avedis Zildjian was making some pretty decent cymbals just four hours up the road from Elton Musical Products.... so if I was Elton's products manager I would have sent a truck up there once a week to grab a load of blanks and stamp my name on them.... seems like a logical business arrangement to me.. :)
It makes sense geographically, but my guess is that even any of Zildjian's seconds would have cost more than what Elton was apprently willing to pay -- otherwise any old Elton pies would be known as worthy vintage plates to look for. That just isn't the case, obviously.
Jaye's probably right in that they might've just been some domestic spun brass cheapies that Elton cold-stamped themselves.
So the mystery continues....