It doesn't actually work like that. Only the kernel is kept, not everything. When you pick a different entry, you're only selecting a different kernel. All the other software is the same.
Do you mean that all the other software is the same as the newest? If I do a weekly patch (dnf upgrade), and that patch includes patches to vim or firefox, and then the next day I boot into one of the older entries in the grub menu, I should get the newer firefox and vim and the the older?