i'm pretty sure all the replacements are a 1 piece hubbed rotor, including from classic. i could be wrong. if you end up ordering from them, i would get a 'for sure' answer beforehand.

the pontiac manual specifies that replacements are 1 piece. OE used two piece on 67-69, but the 4 piston brakes require a smaller hub design. there are less expensive ones than what classic sells. they are definitely a 1 piece design though.