39 tonner wood bed question

[NCSUDucker]

There is currently no bed in the truck. I do have the metal strips and bolts and a piece of the original bed for the profile. This is at least one thing I feel comfortable doing since I'm a shop teacher. My question is, are there wood supports that go under the bed from side to side for the front to front pieces to rest on? Otherwise that is a long span from front to rear. There is a lip that runs around the bed except for at the cab. Appreciate any input you guys might have.