I replaced my hatch the first couple of month of ownership - afraid I can't help with the Mk6 lock
Depends how you receive the replacement hatch - if they chopped the loom you need to remove your own, the ideal is for the loom to be removed with the hatch - takes a bit more effort to remove but saves you time on the install.
once you have disconnected the loom, dont let the hatch close...dont ask how I know!
The other bit of advice I can offer is try to get the hinges too, the spline bolts visible when you open the hatch can be difficult to remove, only a nut on each hinge under the headlining.
The Gti spoiler is notoriously hard to remove, there is 2 pieces to it - the outer painted part and inner mount that contains the brake light the outer fixes onto.
Many people have broken their painted section attempting to remove it, the inner section does not come off in one piece unless you are very talented body work type - I would take this to a body shop to swap them over.
My inner part of the spoiler broke, outer was fine. My replacement hatch was off a Tdi, no spoiler and I am enjoying the clean lines.
HTH