I had an issue with Max's weight about a year ago, he's always had a pouch morning and evening, but I was free-feeding dry food all the time, and that is very high in fat apparently, and can contribute to them becoming 'rotund' shall we say
I've had to reduce the dry food intake, and up the exercise level as he's an indoor cat.
However, the only way to know for sure is to get a weigh-in next time you're at the vets, it can all depend on their build etc, so whilst there may be a bit of a saggy tummy, it may not mean overweight (at least I don't think so anyway).