To be honest, the harmonic balancer appears to wobble on both of my cars too, if I am looking at the front face of it. When I look at the drivebelt groves however, it appears to be spinning smooth and true. The only way it could wobble would be if it were loose on the end of the crankshaft, or if the end of the crankshaft is bent. Both scenarios are extremely noticeable in the way the engine is running.
I don't even know of any reason why they would be messing with the balancer, unless they used the bolt to crank the engine over to get to the torque converter and flywheel bolts.