Is that all the bands are for ? Leaving the country
Sorry I don't know anything about birds
I haven't really felt her body , I didn't know their was anything to feel for , but I will feel later .
Looking at some pictures maybe she does have a belly
Bands these days more identify a breeder and hatch date. They used to be of great importance to prove the bird was imported legally, but they no longer allow imports of any parrots for the pet trade (in the US at least). Virtually ALL parrots in the US are captive bred (unless you adopt an older bird who was wild caught, but importing wild caughts ended in 1999 or 2000 I believe). Parrots can also be microchipped for identification

I'm wondering how old your girl is? Open bands like she has is what was put on wild caughts because their feet were too big to slip a closed band over (they can only do that with babies). Does it say anything on it?
Parrots do tend to have a little "beer belly"

She's a small bird, even her feet and beak are small. If she is underweight, it isn't much and so long as she is being fed a healthy diet and is a active bird, her weight will quickly adjust to a healthy point. If she hasn't been, a vet visit may be helpful to make sure she is a good weight (or what a target weight would be for her and what foods to feed to get her there) and to test for deficiencies or disease.