Can't say that I've looked at that water pump specifically, but I've never seen a water pump that DIDN'T have a weep hole. I'd bet money that yours has one.
The most common failure mode for a water pump is for the shaft seal to leak... in which case coolant will come out the weep hole. According to several manufacturers, a SMALL amount of coolant (just slightly wet) is no cause for concern and does not indicate a failure... but I have to wonder if this is just their way of avoiding certain warranty claims.
The second most common (in my experience): bearing failure. The bearing will become loose and/or noisy.
Third most common: loose impeller. The impeller can become loose on the shaft so that it isn't spinning and pushing coolant properly. Can't say whether this is due to improper machining, assembly, or something else, but I've run across it a few times. The water pump will exhibit no visible external symptoms... the complaint will be related to coolant not circulating (overheat, boiling over, no heater, etc.).
