As Jennifer, Stefanie Powers keeps her fingernails rather short. The fingernails of the hand with 'blood' on the fingertips are much longer.
The establishing shot of the Hart mansion at the end of the episode shows the Bentley convertible only used in season one as it was replaced by the Rolls Royce Corniche in season two.
There were two jewel thieves, but one of them (the blonde) mysteriously disappears just before the car chase. The Harts only catch one of them, but declare victory anyway.