Yes, it is possible for the ballancer to have moved. An easy way to still use the harmonic ballancer is as follows; Remove all the spark plugs and break all of the insulation out of one and weld a bolt or anything that will stick out of the sparkplug down into the cylinder. Now screw this into the hole where the spark plug used to be [make sure the piston is at the bottom or close to it, now turn the engine over slowly in a clockwise direction till the piston contacts the bolt, make a mark on the harmonic ballancer where the TDC of the timing mark is, now turn the engine over slowly in a counter clockwise direction till the piston contacts the bolt and make a mark like you just did on the harmonic ballancer, now take a steel tape or some other way of measuring the distance between the marks, divide this distance in half and that is true TDC of the engine. Make this a heavy mark so you can see it with a timing light and time the engine accordingly. [I'm sure you will remove the bolt after the 2nd mark was made on the harmonic ballancer]
This will work if some one has installed the wrong front cover and the timing marks are not where they should be in relation to the crankshaft.
I hope this will be of some help.
