Deve,

Here is a factory pic of the LH mounting circa '51 which as you know factory shots of these areas are rare.
https://www.flickr.com/photos/advance-design_parts_co/12315086065/in/album-72157640522200463/
The stake pocket has two holes in-line that correspond with the RH/LH brackets.
https://www.flickr.com/photos/advance-design_parts_co/8129182883/in/album-72157631867396207/
This shows my '50 install, in looking through the 1953 full line brochure it appears to be the same (LH), the RH accessory is exceedingly rare and has not appeared in any photos I have.

1950 Chevrolet 3/4-Ton 3600
More pictures on Flickr