Since you have a GC now, you do not need H1-B papers and I-94 for your trip to China. However, I will highly recommend to keep these records safe and secure as you may need them during your Citizenship process later or for your Selective Service's - Status Information Letter (depending upon your case, might be needed during the Citizenship process).
Have a good time in China and do keep an eye on the Eligibility Requirements for the Citizenship down the road.