Don't replace a plastic crystal with glass!

: A few weeks ago, I posted this...
: http://www.chronocentric.com/forums/heuer/index.cgi?md=read;id=51482

: I'm wondering if the experts know what's the shape of the crystal.
: I see it domed but it was previously buffed... I'm wondering if
: this used the same crystal that an 1163 Siffert has where it
: rises and bends way above the Tachy...

: Trying to see if I may be able to source from Nakai a crystal but
: not sure if an 11630 crystal work either...

: Let me here the experts...