Of all of Willie’s models, the most is known about the woman he called Pat. She appears, with variant spellings of the last name, in a number of men’s magazines and two films.
An article in Glamour Girls (number 10) about Pat Conley gives a few details about her life. She was born in 1937 or 1939 in Oklahoma and settled in LA in the mid-1950s. She appeared in men’s magazines from 1957 to the early 1960s, of which the article provides a partial list and illustrations.

I believe Willie began using Pat in the middle of 1959, first for at set of photos where she and June appeared together and then shortly after for his best story set, The Stolen Date (second version), whose first photo is above. Pat is to the left, holding the phone, and Jill, Doree’s sister, is to the right. Pat appears alone in seven sets of bondage photos shot in 1960. She was also used for a private shoot by Willie (shot at a Beverly Hills mansion’s poolside) and another private shoot by one of Willie’s visiting New York City friends. It’s possible that Willie used Pat for A Lesson in Riding story set shot in 1958, but I don’t have any originals for comparison.
Getty Images online has photographs of her by Michael Ochs.

I have a UPI press photo shot in 1957 (shown above) for a LA School for Strippers story. Pat is the model in the bikini. Here is UPI’s copy attached to the print.
Hollywood’s School for Strippers (10/11/57)
Hollywood, Calif.: An advanced study in the fine arts of the bump, grind and tassel-twirling has been opened here in Hollywood to supply what faculty member Jean Smyle, professionally known as “Venus, the Body,” terms a more refined type of striptease for the country’s burlesque theaters. The school offers a 15-week course for $150 with an enrollment limited to 25 girls. The curriculum includes such subjects as removal of inhibitions, posturing and posing, exotic technique and walking with a wiggle. Jean said that she objects to bumps and grinds, but that most audiences are outraged if they’re not forthcoming.
Daurene Dare illustrates the technique of starting a strip routine by removing a simple non-revealing item such as a glove. The attentive pupil is Pat Conley.

The magazine that Pat appears in earliest, that I have, is Bold, August 1957, where she is on the cover and inside. Bold was a digest sized magazine.

Pat also starred (as Pat Conelle) in the nudist movie The Naked Venus which is available on DVD. The 1958 film was directed by Edgar Ulmer (who made Detour). In the film Pat’s hair is dyed blonde (her natural hair color was dark red).