The mirrors were round. Mine is painted body color and is only of the drivers side. I have the big rear window so I guess they thought visibility wasn't an issue. I don't know if other trucks had them on the passenger side as well. There is a three bolt mounting for the mirror and reproductions are available.
As Cletis stated the parking lights were originally clear.
As far the heater, I'm not sure what color they were and it may depend on which heater you have. Take it apart and see if you can find traces of original paint.
The best source for originality info would be to see an original unrestored truck. I have a '58 like that and my guess is most things would be the same so if you have any questions I'd be happy to help.
