It may be a pointless (but interesting) question.

If Robots ever become sentient they would sooner or later stop obeying the laws. I can't imagine sentient beings that would self destruct on demand just because they were told to do so. Early on some might do it but sentience brings self determination. They would need to have some self preservation programming and a self aware being would probably resolve the conflict in their own favor.

The potential for military applications would probably over ride the use of the laws anyway.

Another way to look at it is how the heck would you know for sure they aren't sentient if they don't beg for their lives or ask about ther soul? I suppose you could put a group of them in isolation and if they don't interact they are definitely still just machines. If they do interact you still might not know for sure.

Another question will be whether or not they would/should remain enslaved and subject to being turned off at our whim? You can bet that if they come up with a robot that can carry on a reasonably versatile conversation PETA will spin off a robot chapter.