G.B. Mason stitching horse ID & restoration

[IlluminousCorvid]

I found this lovely old horse stashed away in an old leather shop in northern Oregon, and am lucky enough to get to play with it and do some restoration work. It has a maker’s mark of “Randall&CO CIN O.” and a name branded on it, G.B. Mason. I don’t know if that’s a company or an individual. I’m thinking it was probably a saddle maker from the Pacific Northwest or Montana, possibly even a hundred years back or better. I don’t know much about stitching horses but I think it’s a left handed harness horse. 

   I’d love any info or links to where I can learn more, as well as any thoughts on restoration. I’d say I’m a lower level journeyman at repair and restoration of hand tools but this is a little different. 
 For whatever reason, no matter which way I orient them a couple of these pictures are posting upside down, sorry. 

Edited January 3, 2022 by IlluminousCorvid
More info/pics added