You might get lucky, but why risk it?
Probably it is best to be there. In principle, the inspector ought to verify working smoke / CO detectors as part of their inspection. We have had three inspections in the last five years and every inspector has verified the existence and function of most or all of our devices.
You are truly at the whim of the inspector. Just because others have "gotten away" with the inspector not actually verifying it doesn't mean that they won't. They certainly have the authority to do so, and the authority to fail the inspection due to the deficiency. So...You might get lucky, but why risk it?
Personally, I try not to annoy inspectors on the idea that I will see them again sometime, and I might need their goodwill in the future.
Just my $0.02...
All the best,
BG