Yeah. If your case is well ventilated, to the PC it doesn't matter how many fans you have
It just luck that gives yuo more fans, though more doesn't mean better, since for instance if you had fans everywhere doing different things like blowing in and out, you could have a problem where all air is getting pushed around, and hardly any is being removed.
You have to think how air would move before setting up fans.
Like for instance if you had a space for a fan where the CPU one is, it'd be good to have a big fan blowing out hot air, so that air travelled from the CPU one (the one that would get hottest most probably, and video card too) to the big fan exausting heat from inside, blowing out the hot air!
You would then have one at the front or back blowing in cold air, making a circulation loop.
So as long as fans on components are moving air, and something else is pushing it out, you have no problems.