Well, it's double thick anyway -- 1/4". My own M15 is clearly double-paned (because it's delaminating) but is only 1/8" thick.
If worse-comes-to-worse I'll salvage some parts, including that "upgrade" pane for my unit.
I wish I had more room in my house and lived closer — that’s about as good as they get.
It’s hard to tell, but is that double-pane glass on the cover?… I’m assuming it’s not?