The make and model of Samantha Taylor (Julie Andrews)'s luxury car was a silver 1968 Mercedes-Benz 280 SL [W113] convertible. The make and model of George Webber (Dudley Moore)'s luxury car was a creme 1976 Rolls-Royce Corniche Series I convertible.
To find a "10" for the film, director Blake Edwards originally scouted a variety of locales such as coffee shops, talent agencies, little theaters and model agencies and went to a fashion show where a dozen top models screen-tested underwear of their own choosing. Edwards then decided that spectacular beauty is no substitute for acting talent and that the ability to market products is different to carrying a major acting role in a major motion picture.
The level of George's brandy when he is drinking at the bar. He tosses it back and the drink is very nearly gone but when he smiles at the blonde sitting to his right there's more in the glass.
During the rescue scene where George steers the catamaran over the semi-conscious David, a close up of George right before he falls into the ocean shows that he is wearing prescription eye glasses. He tumbles into the water, and quickly emerges, now wearing sun glasses.
When Samantha Taylor uses the operator to phone home, she asks for a number in the 275 prefix in LA (which was all 213 area code at the time). Although George Webber home is clearly located in Malibu, the 275 prefix in the late 70s was located in Beverly Hills. Additionally, the film doesn't use the now standard convention of unassigned "555" prefix phone numbers, and gives an entire seven digit number - 275-0187.