You can clearly see from the pics of the original catalog that it looks to be n original bass drum and not a conversion..Indication of this is the vent hole underneath the badge.. If it were a floor tom conversion, the vent hole wouldn't be underneath the badge, as you can see from the original catalog kit, there is clearly no vent hole underneath the badge on the floor tom..
This is just my observation..So in my opinion, it looks to be an original bass drum, and not a floor tom.. The thing that makes this kit funny looking are the over sized toms.. Also, the finish does look to be tampered with..