Omega ST 511.0470 Crystal Reference and Size Help

I am trying to identify the correct crystal for an Omega case reference ST 511.0470.

I have looked through the available case-reference and crystal information, but I have not been able to determine any reliable correspondence between this case and a specific Omega plexiglass reference.

The watch needs a rectangular plexiglass crystal and the crystal groove measures 21 by 21 mm. From photos I found online, it's sitting about 1mm above the case.

Could someone with access to an old parts catalogue please help?

I found a catalogue containing it. Here it is for reference.
crown 06922321
glass 062PN2189

Now comes the fun part of sourcing the plexiglass. Anyone have a 062PN2189 for sale?