Well, I've accomplished something similar through a trade glitch: I was trying to get a trade glitch to occur by unplugging the link cable while trading two Pok?mon, in hopes of getting an unusual Glitch Pok?mon. I never did get a Glitch Pok?mon, but one time a Doduo that I was trading lost all of its associated data, setting its level, all of its stats, and its ID No. to 0, and replacing its moves with the Cooltrainer glitch move (which is HEX 00).
Both my trade glitch and your saving glitch are examples of the game failing to save certain parts of a Pok?mon's data, while saving others. You have to be extremely lucky to get it to work right, though. I don't know whether to approve this, because although it is a real glitch and could possibly unlock the ability to find more glitches, there is so much randomness involved that it would be near impossible to duplicate any particular glitch that this causes.