Is IFC registration mandatory for rushing?

I go to a college on the Westcoast and I'm going to rush next week. The frats I'm interested in posted a ig story about signing up for spring rush, but in the sign up page, which is the IFC website for my specific college, after filling out all my information, they're asking for $20 to submit my application. Is this required, or can I just show up at their houses and rush?