I really see RandomAngel's point.
If you truly want to give those things, be a bit assertive about it.
My vote: Ask them if they want you to bring the stuff over before the shower.
I'm w/ RandomAngel. Pile all the stuff together, get the parents-to-be in the room w/ the stuff, and say, "Go shopping. Take what you'd like, and then you can modify your baby registry or let people know, so you have less chance of getting a new one you don't need."
I might even (bcs I'm willing to waste the energy) pile it all in the van, drive it over and have them stand by to cull as we unload (or, put back in). Then I'd drive all the stuff they didn't want either back to my house (in case they changed their minds in a few weeks) or to the Goodwill.
I know that in passing down kids' clothes I've taken to saying, "sometimes hand-me-downs can be a burden, so if you have the slightest hesitation, say no!"
RandomAngel, my ILs wanted to buy the crib, and we said, "No, we will." Mostly because it felt important to us, symbolically, to provide the bed our new family member would need. But also because it was the *most* essential, so we knew we could get it into the house when we wanted it.
If that family member wanted to buy the crib, they needed to have brought it up more than once, especially as time got closer.