Fuel Door Upgrade

I'm interested in upgrading this part: "https://parts.mazdausa.com/p/Mazda\_2012\_MX-5-Miata/Fuel-Filler-Door-Chrome-Finish-soft-top-only/94313672/00008RD20.html." However, it says that it's for soft tops only. How can that be? And of course, I'm not seeing anything like this for hard tops. Is anyone familiar with using this on the PRHT model?