Johnny is right.
The pictures below are of my '49 3804 (1-Ton pickup). This is what your '49 1-ton should look like (if still original). And FWIW, ALL Advance Design 3804s (pickup) have the same 9-ft bed.
The first one shows the linkage from the p brake handle (bottom) to the crossbar. The second photo shows one side of the frame -- outboard end of the cross bar to the rear axle brake assembly (cable with adjustment).
As you can see, at no point do the cables from the brake drums connect to each other thus such a part ayou show is not even a part of the design. Probably a lighter truck or a newer truck.
Hope this helps.
Otto -- Do you have a 1-ton you're not listing in your signature line??

Of course *your* truck doesn't look like that. *your* truck is a 1/2-ton. Despite the sheet metal similarities, 3100s and 3800s have *very* little in common. Hence the 1-ton specific forum (um, aimed at 1-ton owners

)
John