Short bed on long bed frame

[Truck Guy99]

I am about to get a long bed 88-98 chevy pickup bed trailer dirt cheap but the bed is just about shot. I want to mount a toolbox on the tongue but it will hit the bumper so I looked around and found a service bed off a 95 but it's a short bed. I want the service bed because I'm building a mobile tool hauler. Will it bolt on to the long bed frame or do I have to make mounts?