Totally agree with you. My C5 numbers are wrong (and I’m guessing are last year’s numbers), but as you say, NFI about trusting LG online.
I have IRL updates that I feel quite confident in (but still can’t decide if I’m getting a G5 or C5):
G5 - Bottom screw is 10.25" from bottom VESA pattern: 300x300
C5 mount is on a hump - Bottom screw is 13" from bottom, VESA pattern: 300mm x 200mm
So, I’m gonna agree on the 13.25” number, give or take! Thanks for the correction.