Unfortunately, the CB 3180 model has a couple different keyboard manufactures which means it makes it difficult to swap out missing keys or plastic brackets. Therefore, here is what I found so far to help distinguish between the different keyboards. If we don't happen to have any used keyboards left at the time, I can send you new keyboards to install instead.
Keyboard 1
Black plastic brackets under keys
Symbol on the back of the keys =
Clips on the back of the keys are more spread apart than keyboard 2
Can NOT hot-swap keys with keyboard 2
Can hot-swap keys with keyboard 3
Can NOT hot-swap plastic brackets with keyboard 2
Keyboard 2
White plastic brackets under keys
Symbol on the back of the keys =
Clips on the back of the keys are closer together than keyboard 1
Keyboard 3 - (Our stock we purchased from Dell)
Black plastic brackets under keys
Can NOT hot-swap plastic brackets with keyboard 1 or 2
Can hot-swap keys with keyboard 1