My mobo has 1x16 PCie slot looking at this - https://www.cpu-upgrade.com/mb-MSI/P67A-GD65_(B3).html
Quartz was referring to the cards themselves, practically all motherboards have a 16 lane slot.
Your board says PCI-E 2.0, but your CPU is actually PCI-E 3.0, though I think there were some that supported PCI-E 3.0 with a BIOS update.
It is irrelevant to the 3060 and 6700 XT anyway because they both have the full 16 lanes so they'll lose very little performance.