I suppose, although if the student is able to show the prof with the tools that the chip they have (which based on the story should be visually identical or very similar to the rest of the chips) behaves incorrectly, that test can be repeated many times. It's possible the student could have acquired it elsewhere and is snowing, but even if that's the case the fact that they can do the analysis and show (and waited so long in the class to get there), and have the history of asking for help throughout the course, all add up to pretty powerful evidence IMHO. The prof could even do his own test with the chip if he doubts. It seems hard to believe that one student would intentionally try to "cheat" by making his life much, much harder. It's surely a path of much less resistance to just follow the book.

Yes, although just having the faulty hardware isn't enough. They also have to use the tools to show that it behaves incorrectly, which is surely a lot more work than just following the book would have been. That is the part that is easily reproducible. The student already knows how, so in a few minutes he can set it up in front of the prof and show him. The prof needn't do anything other than watch for a few mins.

If more of these cases crop up then you should get suspicious, but you also need to consider the impact of giving a student the wrong chip and expecting them to succeed! I think Blackstone's Ratio should apply here personally

As a teacher, my first rule is, be kind. Sure, there are people who will take advantage of the situation, but they are not really taking advantage of me.

In this case, I'd have a harness that ensures the parts they were given work as advertised, and make it the students' responsibility to report within the first 3 days if it is not working.