Yeah, I hear 20% crabs to 80% big juicy apples is a done thing...
I say go for it. There's no real way for you to know what they are without a science lab...Apples are like dogs, they have interbred into thousands of varieties over the years, and what you may call cookers/pink ladies/granny smiths etc are just a closest description rather than being of the actual cultivated variety you find in supermarkets...
Besides, they're in your garden. make the most of what's close at hand!