That information is not on-line for 55-57 trucks.

For 1954/55st trucks:

3103: 3020 lbs (cab and no bed)
3104: 3285 lbs (cab & bed)
3105: 3490 lbs (Panel)
3106: 3770 lbs (Suburban)

So, for earlier trucks, the Panel/Suburban body/doors (no seats) weighed about 500lbs?
For 1958, 500-600 lbs

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.