Here's the info on the board (it makes sense that you couldn't find much info on it, since it appears to be from a pre-built system). http://www.asus.com/Barebone_PC/V_Series_2530L/V3P5G31/#specifications
Since it does seem to be from a pre-built system, I'd say that you're right about not overclocking with it. BIOS's on pre-built systems are usually locked down pretty tight to keep you from being able to OC. It's still may
be possible if the BIOS will let you change the FSB and voltage. He/you just needs to check and see.
Still, the best option to OC with that system will probably be with a program like SetFSB or ClockGen.