I've seen a video, where you remove the lcd+digitizer from the "replancement assembly" and then you can just use this part. I'm not sure, if there electrical identical, but there is no reason for.
I just got this issue. I've got a 3g version and my replacement assembly has got a different layout for the screws at both short sides and one close to the sim-card tray. But is it just a mechanical issue or are they also electrical different? My hope is, that I can mechanically modify (remove wrong screw position with a plier). More than the half of the srew positions are ok.