Orange color on inside of TOTO drake

[dcp]

Just bought 2 new Toto Drake CST744S#01 toilets based the great info from this forum and the first arrived today. It's in good shape as far as I can tell, no cracks, and trapway feels smooth. The only weird thing I noticed is this orange color on parts of the inside of the tank. I called Toto about this and they said it was nothing to worry about, it's just part of the kiln process. Just want to make sure the experts here agree. Picture is shown below. The toilet was made in Mexico.

One other question, if I ever need to replace the fill valve, can I just get one of those Korky kind with the flapper, or is there some other type I need?

 

[Jadnashua]

It think it's just the ceramic underneath that the coat of glazing didn't cover. I don't think it's a big deal. Porcelain is pretty dense, so it shouldn't be an issue, but I'm open to correction!?

 

[Sponsor]

 

[Terry]

They sometimes have that on the inside. I've never worried about it. I have sold thousands of these with no issues.