When you say "silkscreen" i assume you are talking about the maestro?

Logic tells me that the diaphragm itself has to be silkscreened before assembly.

A bit disappointing that QC got this bad.

Obviously it can't be both. So, we're left to question who's QC was the worst as i am guessing that the hydroforming of the diaphragm material was outsourced.

I think it's going to be difficult to tell for sure. But, to me it seems like final assembly is where this kind of mistake would occur. I think it'd be easier to explain mis-numbering in the final assembly than to make a mistake silkscreening the wrong type of material.

All pure guessing on my part...............