I'm pretty sure the chains are all the same. I've had 03 heads on Teksid block and used my 01 chains. My buddy gave me a spare chain from his 99 Cobra and it looks the same as all the others I have.
The secondary chain gears are different. Older heads have gears with a separate key way. In newer heads, the key way is part of the gear. The gear bolts are also different.
I've redone 2 96 engines using the FRPP chain set for an 03 by reusing the B-Head secondary gears.