[Boatanchors] PTO question for R-390/URR

[Bob Young]

I bought an early Collins R-390/URR with a Cosmos PTO in it, can I assume 
that this is not original and the receiver has to have been modified? (It is 
off about 9 KHz end to end) The reason I ask is I am interested in a Collins 
PTO on epay but don't want to buy it if there will be extensive 
modifications involved, the receiver seems to be all original otherwise. The 
PTO plug (6 prong?) seems the same but there are several wires on the front 
of the Cosmos that run under the PTO that are not on the Collins or I don't 
see them anyway (I also have one with a Collins PTO). (These are both 390's 
they are not 390A's) Thanks,

Bob
KB1OKL