All Thoroughbred A's and B's as well as Bartons are factory unlocked.
On certain mobos however, with
2500+ or 1700+ you'll get the multipliers from 5 to 12.5
and with
2700+ or 2800+ you'll see the mulitpliers from 12.5 to like 22
If you get nForce2 chipset mobo, you'll have no problems all multis are available + they're PCI locked for overclocking galore.