Optiplex GX270 SFF - Can I use 4G RAM?

The RAM specs for the Small Form Factor on the Optiplex GX270 say 2Gigs is the maximum, but the deskstop and mini-tower list at 4G maximum. Likewise, there are 2 slots (SFF) and 4 slots (Desktop) on the motherboards.

Can I put a pair of 2G sticks in the SFF to get 4G and assume that when it was designed, 2G sticks simply weren't available? Or does the SFF just max out at 2G and can't handle 4G and that's all there is to it?  Thanks . . . (running XP)