I have a Scott R75s (~1974) and the acrylic window is glued into the faceplate, which is a heavy aluminum extrusion. The original glue looks like yellowish hotmelt. I'm sure it's something else, but it held the bead shape like hotmelt glue and peels off the acrylic easily. It definitely did not do anything solvent like to the acrylic window. I tried using hotmelt, but the faceplate is so massive, it cools too quickly to stick for long. I have some Barges contact cement I could try. Any other suggestions?