New Rig

[PaHumBug]

Hey guys, I've been away for a while but I just picked up another H2 and have some questions. This is my first lifted H2 (6 inch FabTech), all work was done prior to my purchase so I'm in the dark. The spedometer is reading about 7 mph faster than I am traveling, which seems backwards (bigger tires should read slower, right?) The tires are very new so I wonder if the previous tires were larger than the ones currently on it. Can a dealership correct the speedo? Also how can I tell if it has been re-geared. It's seems to shift good and have normal power. Would it be really noticable with 37 inch tires if it wasn't re-geared?