My iPhone 7+ didn’t have gaskets or sleeves, bought directly from Apple, SIM free/unlocked. I’m the 1st to open it.
Oddly enough, my iPhone 7+ never had these foam gaskets from the factory.
I bought it new online, SIM free/unlocked from Apple and I’m the 1st to open it up.
Also be aware that the battery connector might stick to the bottom of the steel bracket. This part had me a bit puzzled at first. lol
Just gently pry the connector off the steel bracket to release it and be sure the connector isn’t allowed to accidentally reconnect to the board.