Adding Cargo light to a 69 C-10

[mnunn454]

Looking at LMC's catalogue, it appears cargo/3rd brake lights (at the top of the cab above the back glass) didn't appear as optional on Chevy/GMC trucks until 1970. I sure would like to add one to my 69 C-10 while I've got it torn apart upgrading the interior.

Four Questions:
1) What should I buy?
2) Since the cabs are the same shape, is it as simple as sawing a correctly sized and placed hole in my 69 cab and mounting/wiring a 70 light in it?
3) Anyone done this before?
4) Anyone got a picture of a 70-72 with the light factory removed so I can see the hole's shape and size?



Thanks,
Mike