Nope, nothing past the PII's were unlocked, though a few P2 233's, 266's, and 300's were found to be unlocked, they clamped down on that by the time the rest of them came out. To my knowledge, the only unlocked Celerons would be ES's.
Yes, but did it make any difference to your cpu speed? How many MHz was it running at? Some mobos allow you to change the multiplyer in the bios, and even though it still boots, it has no effect on the cpu speed.