Cant find a break down of model but these were first introduced in 1982
FCG20N6
Usually means
F Forklift
C Cushion tire
G Gas fuel
20 should be 2000kg 4000lbs (At 3500lbs sounds like its been derated due to a hung on attachment such as a sideshifter)
N6 maybe a chassis version or possibly Nissan engine but not sure. Other than that all I see is the diesel versions would be FCD20Z6.
If u need specs or what not I can try to help you out as I do have some info for the truck.
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