[Arran]

 I think that the chassis in any 1936 model Philco is fairly well bolted down, the 1937 and 38-116 models are different in that they sort of float on rubber mounts and are not bolted down. I think that they would not be able to mount the chassis in any other fashion in a model 680 Philco other then bolting it down, the chassis is vertically mounted. The set will weigh more then 60-65 pounds with cabinet and speaker, the chassis would weigh at least 40 pounds alone, the speaker and clarifiers another 30. Not sure about the cabinet but  higher end Philcos typically used a lot of lumber in their contruction, no 1/4'' plywood panels here, I would guess maybe another 50 pounds. The whole set will weigh in over 100 pounds for sure.
Regards
Arran