Rick is reading a big boob magazine in bed. He looks at photos of the girls in their sexy lingerie and costumes and tells Jeannine Oldfield that she should dress like those girls.
Being a nice, easygoing girl, Jeannine is fine with that. She leaves and returns dressed for modeling and/or sex. Rick could have just told Jeannine to take her clothes off completely, of course. But lingerie was considered important in solos and hardcore.
In the late 1950s and early 1960s, the girls were usually fully nude and barefoot, especially those who posed for nudie pioneer Harrison Marks.
In the 1980s and 1990s, sexy outfits, stockings, shoes and jewelry were a standard part of the show and rarely came off. Stockings especially were an accessory that stayed on for nearly every model and virtually never came off in the UK.
Then, as now, full nudity and bare feet for the girls are not that common. But some things do change. The majority of the guys in porn back then were ordinary guys and many of them had average-sized dicks. Today, they might not get much work if you can call fucking dream girls work. The oversized, hard as iron "porn cock" is very important to most of today's audience compared to those years. Porn is fantasy. And then, as now, some guys hate hardcore and don't want to see a guy anywhere near a girl they really like.