Apache 40 info please

[blackZ34]

Hi, I'm new to this forum and also to these trucks. I found a Apache 40 (1961 as per the grill ) with a inline 6 cyl that I can get for very cheap. The problem is it's in bad shape.
Frame seems ok, so does the cab and hood, all window are ok, interior is acceptable, but it doesn't have a bed, and the front fenders and the 2 doors would need to be changed.

So, here are my newbe questions:

#1: What's the meaning of the 40 ?(I saw a lot of Apache10 here but never heard of a 40)

#2: Hoe to know if it was a long or short bed (and fleet or step side)?

#3: What year can I pick parts from to keep the 61 look? (the doors, front fenders, bed?)

#4: If you have any other usefull info or tips don't be shy to share with me!

Thanks!