SamyGO

PVR doesn't look working on models bellow C6500 (yet).

"Porting" is not quite possible since you cannot steal functions from those firmware because of it's different CPU, ARM. And your TV has MIPS cpu.
I think it's easier to produce a new hack that records TV steam directly.

I don't know PVR on C series, never used it. When I say PVR, it's simple video recording code, nothing more.
You can capture stream from TV and save a USB device. It's possible with exeDSP injections. for to do that, you needed to disassemble your firmware, exeDSP , and put required codes in it.
The process is harder than making a simple program. Even if you have will, you needed to know assembly language specially for MIPS.
For hint, you can inspect B series PVR hack. In B series, there is in active PVR code in TV and we just activate it.

I don't know if you have such a function on your firmware, if there is, you can make similar tool to activate it.