They aren't immature seeds. Seeds are inside a calyx which slowly crack open, seeds don't grow naked on the plant and don't grow pistils out of them
if you actually popped it open what should it look like without pollination? white "seed" ?
No, there's no immature seed that needs sperm to grow or something (animal-like) like that. It's mostly just bracts, leaves mutated throughout evolution to protect the female sex organs and seeds. They swell up making room for the seed if one develops in it (and that stops the development of some calyxes around it, to make room).
Dicot seed development:
(^^ Cool huh) Another one:
I don't know if the zygote is in the calyx already. If it is, you won't find it with the naked eye. Perhaps if you slice one open and put it under a microscope. If you pop it with your fingers it will just be like leaves and moist.