Leave it locked in a hot car for a few days and come back to us next week.I could've sworn those were plastic as well, but an actual look proved me wrong. The 32mm also has a metal mount. So that leave my 4th most used EF-M lens, the 28mm. Mount still looks good and is still tight, but it's not as old as the 22 and 11-22 and used a lot less.
I'll get back to you in 4 years or so about the mount on the 28mm