I'm not sure if I have discovered something of any importance, but I noted some anomalies between a J and P coded vent today. More specifically, the stamping of the vents in the lids themselves.
The J coded vent holes seem to be stamped flat with no lip. The pictures should explain.
Whereas the P coded vent holes seemed to have a chamfered or raised lip around the stamping of the vent holes.
Has this been previously noted? Does it seem right that on a newer kettle they would make it in such a way that would make it more expensive to manufacture? Or is there a design idea behind it?
I also noted that a K coded lid vent has the flat holes with no chamfer.