Does the athlon xp 2000+ tbred come unlocked

two questions actually
1) Does the 2000+ Tbred come unlocked by default?
2) Is there a REAL Difference between the A and B of the TBREDs?
I hear Bs (steppings ending with a starting with and A and ending with a B) are much better overclockers than the A
Any help will be apreciated

Unlike Palominos, all Thoroughbreds and Bartons come factory unlocked.

All Thoroughbred A's average 2.0 GHz.
All Thoroughbred B's average 2.3 GHz.

Real difference: Thoroughbred B has an extra layer of copper interconnects to reduce interference allowing them to scale 300 MHz more on average.

that means if i am into heavy oc i have to get a B one righto?
And which Stepping should i get and which to aviod
I hear a lot of people are happy with the 1700+ DLT3C or something likethat but it is not available here in my country

Careful there are both DLT3C A's and DLT3C B's but

T-Bred A's have a stepping code which ends in "A": xxxA are T-Bred A's

T-Bred B's have a stepping code which ends in "B": xxxB are T-Bred B's

except if the second letter of the code is Q -- then it's a new Thorton. -- even better.
Thortons come in 2000+, 2200+ and 2400+ flavors.