No and No.
Read earlier in the thread for references to PlaneFun Floats or Seaplane supply. Truly these floats are superior to the ones you referenced.

These guys make nothing BUTfloats and they are D**N good at it. The "accessory" floats are offered be grudgingly by the kit manufacturers, made of materials on hand, on equipent on hand. .
Ihave BTDT.The foam-core floats let your plane fly much better.