This may help.

I changed my crankshaft Balancer, I also changed the bolt, I believed it was recommended by M.B. Doc, he recommended me to change the bolt, see earlier post by me on this thread.

When I bought the bolt they gave me a regular bolt.
Old bolt came out it was (hex, allen dont know the differnce.)

I asked the part guy why is this different, he said these are new updated. New bolt does not come with the balancer.

So, if it has been changed by the dealer he might of changed the bolt as well, some mechanic just put the old one on.

So..if you see new type of bolt, after taking the fan cover off, pretty easy 2 clips and pulls up, little obstruction from the fan.

This may indicate it has been changed.
Another good way to inspect is take a flash light and inspect the rubber in front and back, crank the motor little and inspect the back, sometime rubber looks fine in front but the back is twisted, that was my case.

Also, after fan cover off, run your car and with the help of a flash light look at it carefully, if you notice SLIGHT, and I mean SLIGHT woble, It may be on its way out.

Hope this helps.