When I ordered mine, I emailed Gravity Trading (GT) what the difference was between the messenger bags in Amazon and their website. The gist of the message was IF the description does NOT say "Rapid" then it will NOT have the MAIN zippered compartment. Their website did not have the Rapid name, so I ordered from Amazon through GT and it had the zippered main compartment.
Of course, this was BEFORE they came out with the GT branded bag (which has the zippered main compartment as previous posts indicates) and raised the prices!
So order from GT seller (Rapid or GT brand is ok) but from Amazon (no guarantees from their own website).