One of the mechanical engineers I worked with explained that the reason so many plastic parts are made hollow is not to save plastic but that the shrinkage of plastic when it cools is more pronounced when the plastic is thicker. Especially for a decorative item, which you are trying to pretend is made of metal, it's not good if it sags in the middle!
I'd been looking ror a reason to try Shoe-Goo, so since Richard has used it for a logo, and I need to fix a shoe, I bought a tube! There's no telling when I will try it on the calculator, though - I have more issues with my "street" HP-12C, such as the bezel is all scratched and bent and I need to fasten the PCB, but since it fits in a hole in the bezel, I guess I could just glue the logo on!