Self pollinated seeds can still be different than the parents. Most will be green, regardless of what the parents looked like (unless your mom hosta is a streaked hosta).
But that doesn't mean there couldn't be a nice baby from the seed pod. If your parent is a variegated or solid colored hosta, chances are the babies will be solid colored. They may carry on traits like color, size, shape of leaf and maybe a wavy edge of a leaf. They may make good filler hostas if you have a big property. They can be fun to try, but usually don't amount to much.
Seeds need to mature and that takes about 2 months. Wait till the pods are dry and ready to crack. Nature plants them when they split open. Some people plant under lights in the winter to pass the time.

Also remember that bees are busy too...I you did not pollinate it yourself will see peole refer to it as op ( open pollination). example Spilt Milk x op . If the pod is self pollinated it is refer to as Spilt Milk x Spilt milk.

Still you can have fun with these seeds midwinter.

I think I am correct ...I am just starting to get in to hybridizing. There are people out here and on other forums that know a LOT more than me on the topic.

all you can assume is that most likely only ONE hosta comes true to seed ...

otherwise momma is a hussy ... and you can not predict what the kids will look like ... seems like that sums it up.. lol ..

arent there some FAQ's about seeds???? and try to look back to late last fall posts ... most peeps grow the seeds in the house in winter...

ken