These are mounts to fit the 32x32 RGB LED matrix panel from Sparkfun(https://www.sparkfun.com/products/14646) into the 10x10 shadowbox from Michaels(https://www.michaels.com/black-extra-deep-shadowbox-10x10-studio-decor/10229048.html)
For build instructions: https://github.com/leftyfb/matrixpi
The author hasn't provided the model origin yet.