In Short you can not be 100% sure .
The dam is your best you have to look at a small dam and a average pup from the litter should give you a small dog.
A good working type should be on the small side anyway as large usually means show blood.
Ask about on here for people with small springers for the lines and then take pot luck like the rest of use.
My last springer was small in height but built like a staffy, my latest is 7 months and small and up to now athletic build but who knows what she will be at a year !
But i don't care as she's mine and great !!!!!!!!
Forgot
sire Badger