The hole in the side on the Leica equipment is located on the adapter (also known as a carrier) and not usually on the tribrach itself.
I might be taking a giant leap here, but you sound like you are comparing round base tribrachs and triangular base tribrachs side-by-side (with the adapter included) on the same website. That is usually only possible on a Chinese website. If I am wrong then please ignore me. But if I am right, then please stop what you are doing.
There are a lot of things that you can buy out of China to save a few dollars (non-rotating adapters, cables, etc). Tribrachs are NOT one of those things.
The Chinese ones move. A lot. The build quality in the moving parts and the tensile strength in the materials are just not there.
It might not matter too much for a GPS, but if you are putting a prism (or even worse- a Total Station) on top of a Chinese tribrach then you are asking for trouble.