Originally Posted by RecoveringYuppy
No it isn't.
There was a case (Burdick v. United States) which people think makes that insinuation, but that was more a case of "can you reject a pardon" rather than "does it imply guilt".
Heck, the fact that pardons can be issued because a person was exonerated due to new evidence shows that Pardons don't have to imply guilt (at least in a legal sense.)
Now, that doesn't mean there can't be repercussions.... even though accepting a pardon isn't a legal admission of guilt, it still may look bad to a jury, should someone be brought up on state level or civil charges.
See: Washington Post