i've come across 6 drivers (375), all in varying shape. they have paint chipped off the outside, as they were part of a FOH system.
4 of them have diaphragms with a red dot at the top center; they also have lines 'embossed' onto them which resemble latitude and longitude. the other 2 are totally smooth.
the aftermarket diaphragms i find are all smooth. would i be presumptuous to assume the 4 with red dots are original JBL diaphragms? it's a little confusing as some places i read talk about the original "red wax" factory seal, but that doesn't quite seem right to me. (to put a drop of red wax on a midrange driver?)