Yes they changed the tank and seat mount on the 08 even with the old frame.
But if you want the touring seat not the standard RG/SG seat
Look for part number 52164-10 it is a lower seat touring seat with full passenger size. The others will be part number -08,-09 and -09a they look the same at first glance but do not sit as low for the rider as the -10
Be careful if shopping Ebay for a used one they often remove the part number and try to give the impression it is the 52164-10 when it is not.
Another hint the 52164-10 will say LOW in the plastic seat pan.