Paperweight double meaning
The glass paperweight does have a double meaning. In the book Winston says that he wishes he and Julia could just live inside of it and be protected like a "bubble". This is also ironic as you said that he spends each day in the Ministry of Truth destroying and deleting history while he preserves the paperweight which is an antique. I think the paperweight to Winston is a symbol of trying to preserve the past and hold onto it to show that he is in objection of Big Brother and wants to rebel. The paperweight shows that there was a different past than what Big Brother is telling the citizens and Winston realizes this. He wants to be able to make sure he isn't being sucked in to what the party and Big Brother is telling him like the proles and keeps the paperweight in order to remind him that Big Brother is actually the enemy.