I bough Civ IV from Amazon when it first came out on disc for 40 dollars (early patch sucked), then went to steam to get the expansion and picked up Civ IV+Warlords+BtS+Colonization for $6.50 during 2010 december holidays. YAY!
The old un-patched version worked rather well on my '05 iMac G5 back in the day. So I see no reason why an '07 machine cannot handle it.
When I play the Steam version, now-a-days, on my '09 MBP, I am on near-max settings (note: turn off ANTI-ALIASING--- bug still remains) and on huge map + 19 civilizations with minimal waiting time in modern times.
In short, yes. It should work rather well for you.🙂