I can confirm this latest answer, I have upgraded several Core 2 Duo's (to include Macbook Pro & iMac) to 4 GB RAM. 2x 2GB SODIMM's with absolutely no issue. These specific boards are similar to the G31 chipset boards produced by many manufacturers. Although many manufacturers configured the systems with 3 GB's of memory (as the upgrade from 2 GB), that was never this chipsets maximum memory.
The specifications for this chipset allows a maximum of 4 GB system memory. Although there are many possible chipset options offered (especially during the transitional period from PPC to Intel Core 2), the Macintosh boards offered mostly soldered CPU/GPU configurations in place of ZIFF (Socket T/775).
This really doesn't matter much with the exception of the limitations with CPU upgrades. The RAM is a limitation of the chipset itself, having nothing to do with the CPU socket itself.
The MAC customized boards stayed with the same chipset through the change to the next generation of Intel CPU's (the I Core) then changed several times from 1150 through 2011 chipsets (most supporting > 8 GB DDR3). Although the 2011 chipset does max out at at somewhere north of 92 GB, I believe that outside of the MacPro this is not an option.