If you refer to the Arria® V GX FPGA device migration table from this link, you will find that there is a pin count difference between 5AGXGB1 and 5AGXB7 even though they are vertical migration compatible.
Please refer to the correct Arria® V GX FPGA device migration table from this link.
We have reviewed the pin-out file, and the Intel technical team has confirmed that 5AGXB7 has exactly the same pin layout as 5AGXB1. Thus both of the devices are pin migratable, and there are no pin differences between these two devices.