I'm not seeing any diamond pattern.
Versus the diamond pattern you can see on Highland made handsewns here:
I see a Rancourt handsewn when I look at the Fenmore.
It's more of a triangle than a diamond on the weejuns. Definitely different than the pattern on the OSBs, but Rancourt usually doesn't use a pattern at all. Everything thing else looks to be Rancourt though.