I have seen similar cases for transfer. Be careful, there could be higher chance of mistakes from USCIS for such transfer. So be very careful when you are doing it.
The 485 receipt and both 140 receipts, as well as the I140 approval letter, should be needed. Also a clear letter to explain what you want to do is necessary.
Oct. 1 deadline will add more chance of errors for such transfers. The best scenario is that USCIS will make the transfer and stop processing your I485 until your PD becomes current. The worst case is that they will withhold even this transfer until your PD is current. Or they could totally fail to do the transfer, as was shown in one case.