JC:
Good to hear you are getting Ol' Green back in shape. Of all the '64-'66 Chevy trucks I have and have seen, coupled with the literature I have collected on this era of trucks, I believe the arms and the mirror heads were painted the body color. Standard factory equipped with the small round mirror, the truck would have had a mirror on the drivers side, but not on the passenger side. A matching passenger side mirror would have been added at the dealership.
I have a manual called Dealer Installed Accessory List, including pricing and installation instructions, that was provided to dealerships, specifying the RPO number (Regular Production Option).
These options are identified by the Chevrolet Option Identification Code System. This number consists of a letter prefix and a number from 01-100. The prefix letter of the code identifies the general equipment group, and the suffix number identifies the item in the group. The following is a general listing of the various letter prefixes for the different equipment groups:
A, B, C, D & E-Body Equipment
F-Front Axle and Suspension Equipment
G & H-Rear Axle and Suspension Equipment
J-Brake Equipment
K & L-Engine Equipment
M-Clutch and Transmission Equipment
N-Gasoline Tank, Exhaust and Steering Equipment
P, Q, R & S-Wheel and Tire Equipment
T-Sheet Metal, Battery and Lamp Equipment
U-Speedometer and Miscellaneous Electrical Equipment
V & Z-Radiator, Bumper and Miscellaneous Final Assembly Equipment
Example: The code C42 denotes a Deluxe Air Heater & Defroster (the number 42) from the body equipment group (C).
All of this information is taken from the Truck Data Book, dated Novemeber 1, 1965 under the Optional Equipment Index.
I hope this information is helpful and good luck with Ol' Green.
