I appreciate the discussion. I've found it very informative.
It's worth clarifying that I asked if it was appropriate for the owner to be angry at the CFI. I never said the owner actually is blaming the CFI. I have no idea if he is. I explained the situation to a couple people locally and someone asked if he was mad at the CFI. I said, "I don't know. Should he be?" And that's the question I posed here.
I wasn't really sure how I felt on the issue when I asked. Still not completely sure.
On the one hand, I understand the owner is responsible for the plane. If he wants everything to work properly, it's his job to make sure that happens. As people have noted, hiring a random CFI to go with him to retrieve his plane was not the best way of doing that. "Live and learn", as they say.
On the other hand, a CFI making the "not my job"* argument sounds like a cop-out.
I would expect a CFI to know enough to realize it might be a good idea to make sure all the paperwork is there and do a basic test of the new equipment. It seems like a mark of professionalism to look out for the client's interests by at least suggesting they do that (if the owner is unwilling to pay for the time that takes to do, that's on him).
* making sure the plane was airworthy before flight was the CFI's job as PIC, but that's not the only issue here.