Cats usually stick around where they are being fed, and since she's been there consistently for 2 years, I'd agree it's probably the same one. Protecting her kittens is probably what prompted the attack, like you had thought. It's HIGHLY unlikely it was a different one that actually scratched you, since it's seems like that area is her territory, and she would try to keep other cats away from such young kittens, but it's not impossible that it was a different one. One that could've been passing through and happened to be hiding in the bushes and got scared when your dog started sniffing.
It doesn't really matter at this point (since so much time has passed) which cat got you, so I wouldn't worry about it.![]()