It isn't always easy to tell if a cat has been spayed or not. We rescued what turned out to be a Maine Coon (she was our first rescue and we didn't know anything about cats at the time). The vet shaved her belly to see if there was a scar - and there was. But it was not a neat surgical scar, so we still couldn't be sure. The vet proceeded as if to spay her - turned out she was spayed. He only charged us for the anaesthetic, not a spay operation. She must have run away after being spayed, thus she didn't heal "neatly."
Cats can safely be spayed/neutered as young as six weeks (though most vets won't do it because they don't have experience with animals so small): http://www.winnfelinehealth.org/repo...ly-neuter.html
Our vet's policy is to wait until the first baby tooth falls out. That's when they begin the process of becoming "adults." This usually happens around four months of age. If your kitty has all of her adult teeth, she is at least four to six months old, and needs to be spayed if she hasn't been. Perhaps your vet will do the same that ours did? Though if they shave her belly, if there is a neat scar, that will clearly indicate she has been spayed. If she is less than a year old, whether there or not there is a scar should be apparent, so I don't know why the vet told you that. It's certainly worth shaving a bit of her belly for!!!!!! If they can't tell they can't tell, but to not even give it a try? I'd find another vet. I agree - no need to put her through the trauma of surgery if it's possible she doesn't need it.
And "PM TNR1" means send a Private Message (found under your user name at the top of the page on the right) to TNR1, otherwise known as Katie.
You can also click on the link in my signature line to help find low-cost spay/neuter services. Or you can try http://www.pets911.com/organizations/organizations.php
Just type in your zip, and start calling organizations in your area to see if any know about shelters that provide no-cost spay/neuter or vets or other orgs that provide low-cost spay/neuter services.
Just an FYI: most vets charge more to spay a cat in heat.
And - thank you for rescuing this kitty! It seems like she's a very lucky girl. Any pics?