It would be hard to say if it is original or not without seeing it. Do you have any pictures of the shifter? Also look for evidence of a shifter on the steering column. Most of the hack jobs didn't bother with much more than removing the shift handle from the column. One reason for switching to the floor shifters was that the column shifters would get worn and/or dirty and malfunction leaving you in the middle of the road stuck in gear and not able to shift. Just the fact that the shifter has been messed with doesn't make it a bad truck to consider.
