The first Ventus didn't have them, and people complained about the risers twisting. Mine have a conversion plate glued to the top of the wing so that the castellated risers will fit, but they don't have the deep socket which the risers sit down into on the Mk2
Ah.
I missed that first time around and only ordered one set (two plates).
But I'm a little puzzled now, as each plate is 1.55mm thick (so two would be 3.1mm) and not 2mm (ie 4mm for two).
@mdcc_tester suggested getting a 3mm bridge to keep the stack in 5mm increments, which indicates one plate only.