Ron, with due respect, no they are not "paper tigers". They just need to be done through the proper channels. Get stock housings through independent sources (Mazda -> stewards) and you're good to go. Heck if timing is an issue, contact the Steward before the race, provide the $ and have them ordered early and in the stewards possession. Once used, return them, net cost will be the restocking charge, and I'd bet Mazdaspeed would waive that.
If I'm a rotary guy, and i get protested, I know I'm legal, but if somebody says, "Hey, this lollipop doesn't agree," I'm going to want the paper trail, and it better not start at a competitors 'stock part". Even if the stock part is 1000% legal, the deal is going to smell. So, if you're going to do a lollipop, make sure the process is 100% above board and completely neutral. In other words, Stewards buy the part, Stewards get teh measuring/machining/molding etc done, and Stewards stamp the part and maintain the inventory. If a competitor holds/supplies it, it is worthless. It has to be.
I agreet that trying to quantify the part is critical, but again, the GCR isn't the absolute last word. it can be wrong. Beyond that, how are you going to put 3D CAD specs in it?