Alright, alright, now ya made me go & get my factory workshop manual.
This has an explanation of the model codes.

This code applies to Aussie spec, but Japan produced model B210/120Y cars.

The sample code in the book goes like this. ... K B 2 1 0 S T R X ..... & this is the breakdown

K= Coupe model V= Van model. No character= Sedan model.

B210= Car model.

S= Standard model. No character= DeLuxe model.

T. In this position, A= Auto trans, No character= Manual Trans T=Floor shift control [I assume that T= floor shift auto.]

R= Two door.

X= Destined for Australia.

I do not have the separate book for the Aussie assembled sedans from July 1976, so the code here is unknown to me.

I hope that this helps.

Knowledge? Nah, not really, but I'm old enough to remember my stepfather selling 1000's new from his Datsun dealership. I was 24 when the first of the 120Y's were new & I worked not far from CapMo. They had about a half mile [well it felt like it] street frontage onto Parramatta Rd & what must have been a zillion cars on the lot. I remember the cars well as the low cost 120Y was a big seller & plenty were kept on hand at all times.

The only thing, knowledgewise, that I really need is a passable memory, & the knowledge of where to find my factory manuals, handbooks, owners manuals, advertising literature, brochures & accessory brochures. With these, anybody can be a bloody expert.