Early or mid 2001?

I went to order some steeda pulleys and was confronted with the question of whether or not my car is an early or mid 2001 production model. Is there any way of telling which one mine is? Like visual differences or is there somewhere I can put in the VIN and check it or something? Thank you for any help.
 
If you are ever concerned with what transmission your pony has...

Transmission codes:
The Mustang GT in 2001 had both the T5/T-45 and 3650 Transmissions. Check your driver's door for a sticker and look under "TR" for a "K". If you have a "K" then you have the 3650 Transmission. If not, you have the T5/T-45.