How determine what diaphragm?

[Jakob]

I recently bought a pair of 2441's quite cheap but I'm not sure it's 2441 diaphragms in there. I took of the backplate, and they seem too grey to be aluminum. The colour look much like the colour of the 044 ti's in my 250 ti's. They have the diamond pattern surround and are otherwise plain. No marks or colour code dots what I can see.

Can anyone help me out?

Question number 2: I know some people who uses their 2441's without the backplate on. What does this do?

Thanks: Jakob