While the show has used different model GulfStreams,they always have the same interior. There have been minor changes in the interior over the seasons. The size of the cabin shown is most likely the G450 or G550 which have similar interiors. A G100 or G200 is a much smaller cabin, narrower and not as much headroom when walking in aisle.
The black SUVs used by the team frequently have US Government "G" plates. However, the plates are usually incorrect for the type of vehicle they are on. Plates with prefixes of G12 and G14 have been seen. G12 is a compact sedan and G14 indicates a large sedan, and would be incorrect for use on an SUV. The correct plate prefixes would either be G41 for a 2 wheel drive or G61 for a 4 wheel drive 1/2 ton vehicle.