PCOS is still a mystery in many ways. Because it is a syndrome, rather than a specific disease, it has different ways that it presents in different women.
One study breaks these down into five categories:
traditional PCOS -- anovulatory, increased androgens, no insulin resistance
endocrine syndrome X -- anovulatory, increased androgens, insulin resistance or type 2 diabetes
non-traditional PCOS --anovulatory, normal androgens, obese, insulin resistant or type 2 diabetes
non-traditional PCOS -- ovulatory, increased androgens, mild insulin resistance
idiopathic hirsutism -- ovulatory, increased androgens, no insulin resistance
You'll notice that two of these five do not include IR. So perhaps IR is not inevitable.
That being said, your gyno may see your particular symptoms and he may put them in one of the IR categories even though at this time you are not IR.
This study, on the other hand, focuses a great deal on the issue of IR and PCOS, and puts them firmly hand-in-glove.
Another site says it's only a percentage... "It has been estimated that 20 percent of women with PCOS who are obese have either impaired glucose tolerance or non-insulin-dependent diabetes mellitus (NIDDM) by age 40."
http://www.bouldermedicalcenter.com/...n_syndrome.htm
That being said, you may want to talk with other non-IR cysters (women with PCOS) and see what they say. I'm very strongly IR, so I may not have experience that will help you.
SoulCysters is a great PCOS web site for info and encouragement. You should definitely post here, too! (of course!) but a more specific board may be able to give you more specific answers.
Post and let us know what you found and how you're doing!