If the thought this could be what happened did not occur to you, or you believe that there is no way that it could have happened (despite no evidence one way or the other), then you are lacking in one or the other.
It is within the range of possibility that some pro-Bush group did the forgeries. However it's not the most likely option, for a number of reasons:
1) There is no evidence of it AFAIK, present some if you know otherwise.
2) The more straightforward tactic of attacking Kerry's record seems effective enough, so why a Byzantine scheme such as this ?
3) The party most discredited if, as seems likely by the preponderance of the evidence, the documents are forgeries is CBS News, regardless of who did the forgeries.
CBS News failed to detect that the documents were forged, evidence of sloppy journalism, and jumped on the documents like a hungry shark, (admittedly weaker) evidence of an eagerness to discredit Bush.