Your place for the TI-99 Home Computer Family, with focusing on internal documentation and the TI-99/8
These two MBX joysticks came with the pre production MBX Unit. The left one seems to have been originally black/red like the ones used on the CES 1983 show. It seems that the black shell was replaced with a beige shell when the joystick resistor got repaired. You can see that the cable is still black, the buttons are red, and the stick is red/black. The right Joystick looks very close to the commercial MBX joysticks, but I even found two differences for that one. Both are therefore pre-production versions.