Odd sequence of numbers Datsun trucks.

[pidge]

Just on my one day off a week vacation and was wondering...do the numbers mean anything with regards to model number? Example 320-520-521-620-720-hardbody etc? I’m tired and it just popped in my head. Are they just arbitrary numbers given to those trucks or was it much more.....apologize in advance if this sounds stupid, but just had a brain fart and was wondering. 
-Pidge 

[datzenmike]

The initial number may be arbitrary but the later ones just followed a normal progression and cars were 110, 210, 310 410, 510, 610, 710, 810, 910, B210, B310. Buyers could identify with the newer or older models and like all businesses they rely to some extent on brand loyalty. A previous owner would find it easier to find the latest. Just as there are 7 generations of Corvettes or the  Chrysler 300 series 'letter cars' with each year going down the alphabet to L in '65 when discontinued only to be resurrected in '99 as the 300M.

[MikeRL411]

Also, the then current auto has a middle digit of "1" as in 510. and the corresponding truck middle digit is "2" as in 520.  Later improvements to the basic series have replaced the final "0" with a 1, 2 or higher.  As in "521" truck. Or for example "410" vs "411" sedan.

[datzenmike]

S10, S110, S12, S13, S14

 

[pidge]

Ahhh. Did not know that. Interesting. Thanks fellas. 
-Pidge