NAPA wants to know what model my 1959 C60 Viking is the options are: 4100, 5100 or 6100 The vin is V6M590105823 GVW 21,000 lb 283 with a 5 speed and 2 speed rea axle.

No where on the data plates can I find the required info.
Any help would be appreciated.

Thank you C60