If you are not sure, change it. You cannot see it from outside. And a new one costs you only 59 $ in the improved version
http://www.autohausaz.com/search/pro...8@Water%20Pump
Compared to a blown headgasket this is very cheap.
I would also change at the same time the thermostat, and all fluids where you do not have any records when they were changed last time.