Yes it is porcelain and is a swirl flush....I did see the plunger when I took the pedal off...have to check the back side when I get home...had a heck of a time getting the pedal back on...guess that's why it has a stamp on it Do Not Remove....but you have a heck of a time reading it if you're a big guy trying to get wedged in between the toilet and shower....probably gonna be more of a good time to try and see what's in back to get to the valve lol lol.....It has stopped leaking for now but I don't trust it.....Thanks
From Central Texas
2014 Cedar Creek Silverback 29IK
2010 Dodge Laramie 3500 Dually
My Steelpony....2007 HD Ultra Classic...done up in a memorial to the 343 firefighters who died 9/11
Never Ever Forget....yes I was a Volunteer FF for 20 years........