Hello. My remote key gave up. Tried ordering new, but

89705-50041 discontinued
87905-50907 discontinued also.

So, I've sent mine for repair, they've found that one of the components is faulty which needs replacement but having difficulty finding the part (electronic part).

Now my first question is can I buy an uncut similar one button key and give to them to take the needed part? does all one button lexus keys for models 1990 to 1994 (ls400 gs300 es300) share the same internal components (they look exactly the same from outside)

Second question. If the workshop succeeded in finding the part and repaired my old key. Can still buy a similar shape remote key (like the one below) and cut it and install my old key repaired internals in it. Will it work?