It happens quite a loy with Mustang kits, where a 'B' will have a 'D' panel and vice versa. Bear in mind the Airfix 1/24th scale kit was first issued in 1972, so might not have had the benefit of 'todays' methods and access to the real thing. The big 'goof' on this kit, unless it's been corrected, are the landing gear legs - the oleos are at full stretch!