OldIHC

Is the bed on a KB 1 the same as D2?

no, completely different, UNLESS the D-2 you are getting the bed off of, had a KB bed put on it in it's past life.

I thought I just learned the D2 bed was 49" ID,,K1 box is 48" ID. I don't see why you could not use either bed. It's just a box. Fenders are somewhat critical. Local has 58 gmc box and fenders on a '41 K1. The nicest thing I can say about that marriage is "it's functional"

not saying he Can't use it, he asked are they the same, and no they are not the same visually, lots of differences if you want it period correct, if you don't care then sure Any bed will work on just about any truck,

I see a lot of IHC with Chebbie beds because IHC ones are so hard to find, is it the same or correct? no, will it work yes,

My two "one family" pickups are here to look at. No bed swapping done on them I doubt.
One is a 1940 D-2
The other is an early K series pu.

Other than the length of the bed the sides look very similar to me.
I noticed the same thing in Crismon's book...late D series and early K series looking like they had a very similar bed...earlier D series had a different style bed...
Fenders are different, obviously...
Nice to have examples to look at!