Tomei states that the new restrictor that you press on top of the factory one has a smaller orifice than the OE. The restrictors/check valves that Nissan uses in the decks of the engines are all the same from what I've experienced through the RBs I have in the shop as well as the VGs.
I am just not sure if they are restricting the check valve or just adding a smaller restrictor on top of a bigger one. I haven't dived into that area yet to investigate.