No. it was mentioned that MCP35X is among pumps this heatsink can be mounted on, but not that it's needed for it. Imho it's not needed on MCP350/DDC-3.1[0,5] too. It's 18W versions that sometimes tend to overheat.
As for heatsink itself .. i see same drawbacks in this, starting in what was in original BeiFei's one - bad heat transfer from original plastic case, - imho this time Koolance did more "right way", and not just cooling wise (metallic and not airtight casing replacement), but also size and mounting holes wise (not too sure about the last, but am too lazy to recheck). - As in imho one of main features for such heatsink to have - for it to be mountable on pumps mounted in as many ways as possible, not just one scenario - directly on case wall/floor. Because of bigger size - double tops can be striked out, one should check also how are things with bayrestops, (UN)design mounts probably also are out because of bigger distance between screws on this larger heatsink.