1985 Chevy 1 ton 4x4 dually, can I put a bed on it?

[77c10diesel]

So, I bought some farm land recently and sold my house in town. I am looking for a new(73-87) truck to do hauling, pulling a trailer, and general farm duties.
I have always loved the 73-87 trucks, and have owned many. So, I found a real nice 85 Chevy 1 ton 4x4 Dually that has a service truck bed on it. It was a local Fire truck in central Washington, so completely rust free.
I can use the service bed for a while, but would really like to either put a flat bed on it, or convert it to a standard p/u bed.
I have found a bed, from a dually with good fenders, also local, for cheap. Is there anything I need to know before I go out and buy this truck, and then the bed? The truck started as a cab and chassis, was there any goofy wheel base issues or rear frame issues I would need to know before I do this? It looks like a standard 8 foot bed W/B, but I would hate to find out after its too late that there is a 3in difference or some other crazy thing.
As a side note, my Dad took a 64 Chevy panel truck that was rusted and pulled the body off and tried to put on a regular bed and cab, turns out the panel was a 6in longer W/B. His solution was to install some side pipes off a Camero between the cab and bed. Everyone thought he intended it to be that way or he stretched it. I would rather not repeat that mistake.

[zieg85]

I've seen cab and chassis trucks with 135.5" wheel base and using the narrow rear end.  I've also seen them sold without a dually bed with the standard 131.5" wheel base and regular dually rear end.  It should be on a sticker in the glove box or on the door post as to what the wheel base is

[Blazin]

Dually bed fenders are going to hang way out over a cab, & chasdisrear end.
There could also be wheel base issues.
You can shorten the driveshaft, and slide the Rea end forward. If you lift it, or extend the inner fenders you could run a reagilar pick up box.