This photo shows the print side of the R-6C2c circuit board, which I believe is the third revision version of the TR-63 board. I will add a photo of the R-6C2a from a TR-63 for comparison when I get around to taking one. (So sorry!)
Here's a closer look at the top transistor (mixer). Sony had only changed to these zinc-plated cylindrical packages a few months earlier. See the photo below for a peek at the previous version of the 2T73 in an oval package.
The 2T73 transistor pictured here is from a Sony TR-83 built in April or May of '58, about four months before the TR-65 we are looking at together.
I figure anybody willing to come this far might like a closer look at the TR-63 input and output transformers, the pair of 2T65 output (power amp) transistors, and the 1T52 varistor. (The varistor stands in the corner wearing grey shrink tubing like a good trooper.)