See the project here https://hackaday.io/project/188800-classic-hp-calculator-lipo-battery-pack-enclosure

Print the enclosure with the provided STL files.

Although Tom provides a link to PCBWay to order directly this won't work since it is NOT THE SAME PCB.
I have NOT yet published the PCB.

I used four M2 x 8mm screws to close the enclosure and one fragment of transparent 1.75mm filament as a light guide for the LED.

The STLs can be printed on an FDM 3D printer but for best results I recommend using the SLS capability of your PCB provider. I had good success with JLC PCB (not sponsored, just a happy customer) and their SLS black nylon for other projects. New photos when I receive the parts.

The enclosure is licensed CC BY-SA