It's possible (it happened to me) but it's not likely, because it's virtually impossible for it to "skip". The only way for the counterbalance to be out of synch is for it to be assembled that way. And most people that are going to attempt any work in the bottom end know this. If they don't, they generally don't have the mechanical aptitude to get everything back together and running again.
I'm putting my money on bearings or a crankshaft issue.