pergnan sward/guppie

I bought a female sward at a "mom and pop" pet shop the other day because she looked pregnant and the guy said she was. my guppies just had babies, well one did one is Prego and are in a 55 gallon tank, its not really set up fancy or any thing I just wanted to get them in there so the guppy babe's would be less likely to get eaten. Anyway I have been reading about sward breading and the one said they will have pink bellies with black dots. Well this young lady has a Black belly like my guppies did before they had their babies. She is a white/grey sward and the back half her belly is just black, any way she is not really fat or any thing but compared to my red swards (different tank) she is thicker and bigger in general. (Older maybe) also the pet shop guy said if she is pregnant they are molly/sward babies.
Does any one know if that is even possible? Could I have shocked her by buying her?
I took the no longer pregnant guppy and put her in the breeding net to keep her from eating the babies, right now neither of the other two seem to have problems with the babies.

Also on the pregnant guppy, she started laboring almost a week ago; she has been super bottom dwelling and seams to try to push the babies out with some of the large rocks. I am really worried about her she was doing this days before the other one gave birth and the other never did any of this. Also she has developed what looks like a bleed between her belly and spine just on one side. It’s internal and is just bubbled a bit,
Thanks for any help on an of my fish.
~Michie~
Moba’s wife