I don't think so...she's not listed in the credits (although that's not always accurate) you can see the scene you're referring to in this clip:
http://www.videodetective.com/titledetails.aspx?publishedid=120185
I was watching this movie this afternoon on cable, and I am very sure it's Amanda Plummer. It looks like her, it sounds like her, Bill Cosby's character calls her Donna when he asks, "Donna, what's a Tahitian Titillation?" The only problem is there is no credit for a Donna in the cast list, and Amanda Plummer's credits don't start until the early 80s. But I'm reasonably certain it's her, I have a very good memory for faces and voices.
Here's a more complete version of the scene. Take a look at it and let me know what you think.
http://www.youtube.com/watch?v=NcKSt6fFgKg
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