I've got a couple of these on a table with a 100W C02 tube, one has deteriorated significantly ..

Other than it saying Parker Automation Daedal Division on it I don't see any kind of identifier.

This is used in the beam directional path.

Could I get a 25mm mirror such as the one below and mount it in place of the peeled one? .. or even directly on top of it?

25 mm Molybdenum (MO) Reflection Mirror

Attachment 287184