With a 1:1 dump, the disc encryption is still present.
If you take a current dump, this encryption is not present as it has been removed beforehand.
For all intensive purposes, you will not be able to rebuild current dumps to be compatible unless the disc encryption check is removed by the device.
From what I have read, this does not seem to be the case here so a NEW 1:1 dump will be needed to ensure the PS3 recognises it as a vaild "disc".
A 1:1 dump does NOT mean you will have 50GB ISO files, it just means that all contents of the ISO are still intact and encrypted.