I'm in the process of ordering a 2008 double cab with an 8' bed. It has taken my dealer a couple weeks to track one down and it is supposed to be shipped this week. I need to be able to carry 4' x 8' sheet goods. Now I have found out (while looking for a cap) that there may be different bed widths! I assumed if it was 8' long it would be 4' between wheel wells. Are there differing widths and if so what do I specifically tell or ask the dealer to make sure I get the correct one? (Getting any kind of honest answer out of this guy is difficult - he wants to guess at everything).