I had a long and enlightening conversation with Rogers expert Jeff Burke tonight, who filled me in on the drums I just bought.
The 12," 13," and 16" toms were all made in Dayton as per the serial numbers, according to Jeff, and were most likely shipped to Fullerton with a lot of other shells, hardware, work in progress, machinery, etc. The bass drum is likely Fullerton made, as per that serial number. They could be either Jasper or Keller shells. The drums are Holiday models, except for the BD, which is a Powertone. One of the toms has a label with a name crossed out and Holiday written in pen.
Jeff was about 95% sure that what I have is not a Londoner set, but one half of an Ultra- Power VIII set that could have been pieced together. Most likely, a previous owner, or the music store where the seller bought the drums in 1978, sold the other 24" bass drum, along with the 14." 15." and 18" toms, breaking the big set up into two smaller sets. The collet and collet nose bracket under my 12" tom was for a clip-on hi-hat, because a cymbal L arm wouldn't fit. Or, it could have been installed for a snare drum on special order, but unlikely. The floor tom is a 3-ply. All the other drums are 5-ply.
Jeff put the date of manufacture at 1969 at the latest, and the bass drum perhaps made in 1970, as per the serial numbers.
I have a last minute unexpected gig tomorrow night, so they'll get their baptism of fire then. I put new clear Ambassadors on the 13" and 16" toms. and tuned the drums up. I think they'll sound great.