Noob Questions on my 69

[LongBox]

I think the original purchaser of my new (to me) 69 GMC 910, was afraid to tick off very many of the option boxes. I spent some time working with it today and discovered:

1. The interior light does NOT have door switches, you turn it on with the headlight switch;

2. The "full foam" vinyl bench seat does not fold forward to let you get at the small space behind the seat;

3.There is no cigarette lighter, just a black plastic plug on the dash;

4. You cannot lock the truck up without using the key when you leave, not even by holding the door handle button in,

Some of these features would be kind of nice to have, so I'm wondering if they were available on the 67-72s?

The other question I have is what other years, such as 73-87, have parts that are the same, and by that I mean body parts, suspension parts, brakes, and so on.

Any education would be very welcome, and thanks in advance.