This definately can show that your PD is carried over. But I doubt it.
1. From what you have said, it seems you did not give other documents for PD carrt over. USCIS will not automatically carry over your PD. You need to work with your lawyer to notify USCIS of your two cases.
2. I-485 receipt is nothing, which just verifies that your case is pending. When USCIS process your EAD and AP, or 485 in the future, they will check with your PD. Call them to verify that your 485 receipt is with the old PD.
3. If your Eb3 sponsoring company revoke your I-140, you will loose the PD. I-140 can not be revoked only after 1-485 pending after 180 days. Note that this is the related I-485, your case is job changed to a different company, so better talk with your lawyer.