verifying that linux kernel source release is complete

[Jonathan Wilson]

I have a device (Motorola Z6 phone). I have the kernel source that is 
supposed to match with this phone. I also have telnet access to the phone 
(and can examine things like /proc/*) plus I can grab all the binaries that 
are on the phone (kernel and all modules). How can I verify that the code 
Motorola released matches the kernel on my phone and that Motorola didnt do 
what it has done in the past and deliberatly (or accidentally) left out 
some code used to build the kernel and modules? And also how can I tell if 
the kernel configs I have match the kernel configs used to build the 
running kernel on the phone?

Also, is there any way to see what GCC and binutils version was used to 
compile the binaries?