she could and probably is if there was a male in with her.
first off, give her some nice protein food, boiled/scrambled egg, chicken/turkey (babyfood or fresh) porridge, i give cat biscuits too for calcium/protien.
nest, if she has not given birth, clean the cage, as if she dose, you cannot clean them untill all the eyes of the babys are open, sometimes 18+ days if the runt is behind.
remember not to touch the nest, babys or anything near them, My girl lucy gave birth last week, you can see my thread for comparison to a definite pregnant hamster. she will become larger on the hips, will give off a slight smell (nothing like heat level) she will get frustrated, dont handle her if she gets big like that incase you disturb her too much.
if you reach the 20 day mark from when you got her, with no babys, no swelling then she is fine, if theres any small swelling keep a close eye as it could be pyo, I lost my girl nemisis at 13 weeks old due to pyo, I had her from a pet shop at about 7 weeks old. so it can happen young, but normally its in older girls.
eta:
Younger mothers tend to have larger litters, the older they get the number they give birth to normally will go down, especially if second litter. the average is 8-10, but I have seen a 15 litter, 18 litter and they can reach 20+
babys would be split at 22-28 days old by the breeder, as boys can become mature at 28 days old, and impregnate their mum as she stays with them until the splitting date. when their eyes open you can gently see if you have boys or girls, but its not too hard to tell with syrians, we can help out too as theres some highly experienced breeders here who can give a good second opinion.
by the colours you have described Ild say the brothers where sable roans maybe mink roan, so there could be some of the wh gene floating about, dont worry as the mother will sort out the safe babys from those who are WhWh but hopefully she isnt expecting, and it was just a very butch female in with them
(my sisters female looks like a male, acts smells and everything like a male, being lh i kept checking just in case, but she is just a gender confused girl!)
just a side note: double check all baby foods to make sure no onion/leek/garlic or spices
i find grandpas sunday lunch or the heinz chicken dinner are quite good, but again, check before buying!