Hate to be the barer of bad news, but these trucks command little money.
Keep your build to what 'you' want, not resale.
I say this after restoring a '79 J10........theres little to no market.

Mine:


Step side dosent matter much, 1 owner helps......but, not much, mine was 2nd owner with 87K........

Few tips:
Decals.......chemically strip them, dont sandblast.
If 360 equipped, upgrade the ignition.
Expect 10 miles to the gallon at best..
Most everything for that truck is avail at/on ifsja as suggested prior.
That would include new decals I'm pretty sure......
Build it for YOURSELF......
On ifsja, you'd be lucky to get $1,000 as it sits...
Build it for yourself, pass it down in the family.......

 

Nice info Detour. I'll subscribe as I'd like to watch some progress

 

Yes, if you are going to keep it build it for yourself.
Beauty is in the eye of the beholder and that goes for
vehicles. As for the price, that is up to debate. It depends
on a lot, but condition is prime. If yours is in running condition
with little or no rust (not from midwest or northeast) and has
a good interior, is original (collectors do like to see lifts or upgrades)
you have something. Some owners perfer a 727 auto while others
want a manual. IF yours is running with not excess miles then the
value is far above $1000 like another post says, even in the exterior
condition you show in the pix, but not rust is important.