GPS is used on some 767s
We have a 767 fleet that is about 50% FMS with GPS & IRS, and the other 50% FMS with IRS only.
On the jets with GPS, we align the IRSs (using the FMS) utilizing the more accurate GPS position.
On the jets without GPS, we input stored gate coordinates, or if unavailable, manual Lat/Long entries.
Regardless of where the coordinates info comes from, the other pilot is required to verify their accuracy using a separate source document.