I'm August Abbott, dealer in select antiques, collectibles and rarities x 30 yrs. Give me a few mins to review & prepare your answer. Thanks!
Tell me the measured size of your prints and the subject matter (which birds are they?)
Do you have the provenance on your prints (how they came to be with you) ?
Oppenheimer is a highly respected preservationist which gives me high hopes that your prints are authentic. If they are what I hope they are, yes, there is a very good market for them.
Unfortunately, the majority of Audubon's I've seen over the years are inexpensive copies with very official sounding 'societies' or even museums having issued them as collectibles, etc.. They are generally not.
So let's hope you can make my day - and in turn, that I can make yours
Size and subject are important here; a photo would be helpful as well, though it cannot tell me as much as your own viewpoint and measurement
Take your time. If I sign off before you have a chance to respond, I'll be back on tomorrow/Friday