is there any way to tell if my cat has had kittens in the past?

i follow a lot of accounts with newborn kittens, and i've noticed that every time she hears a kitten my cat will start frantically searching the whole room and meowing. if i show her the kitten on my phone, she pushes her head against it and starts purring. she's 5 years old and was supposedly a stray until she was 3. she doesn't have any spay scars or anything like that, but she's also never gone into heat so we're positive she was spayed before we got her. she likes to "groom" my hair every night when i lay down for bed and is very protective of me like i'm her kitten. i'm just wondering how likely it is that she's had babies before?