SFrazeur is correct.
In the early part of 2002, Federer used a PS 6.0 85 with a HPS 6.0 95 Tour red paintjob (similar paintjob to the HPS 6.1 except a matte instead of glossy finish). Then the latter half of 2002, he used a PS Tour 90 with the same HPS 6.0 95 Tour red paintjob. He then switched the retail PS Tour 90 black paintjob in the spring of 2003.