When mine shattered in the rough not from heat I made a pattern out of appropriate thickness MDF with the holes for handles and bolts and even drew on the pattern for the blackout round the perimeter and took it to window shop and hey presto turned up one week later exactly like the original holes,blackout and all.
Yes there is a fireplace glass but when they identified the remains it turned out to be just toughened glass but mine was the outer glass not the inside glass. And it was cheap like $220