IT still looks stuck together. I have never seen those 2 together but do know glass sticks. It looked to me the back of the Smoky label is what you were showing which is on the underside of the ashtray. I guess I could not see what the picture was showing.
Is there a groove where the 2 meet? Say by the cigarette holders? Not a seam but space where 2 could be stuck. If not stuck you have a very rare unusual item if somehow made this way.
The label was applied after they were made. I doubt it is true label under glass as for instance on antique backbar bottles where a glass window is applied over a foil type label.