Hey, question about dump trucks

Didn't even remember the trunnion mount till that picture was posted. Had one of those on a old truck, Want to say it was a Henderson bed, maybe a Williamsen can't remember. No complaints, that was a pretty good body. Think it had the last stage of the ram on the top though. It was handy being able to un bolt it from the bottom. Doghouse access covers always end up banged and beat up.