That's not accurate; first generation MacBook Pros used 32-bit Core Duo processors as well, as did almost all the early-2006 models; the exception being the lowest-end Mac Mini, which had a single-core 32-bit Core Solo. 32-vs-64-bit was never used for price differentiation within a lineup; Intel's 64-bit chips just weren't ready in time.

Late-2006 models, including the first-generation Mac Pro, moved from the 32-bit Yonah Core Duo/Core Solo architecture to the 64-bit Conroe Core 2 Duo.