The AA express bed isn't two beds welded together, although some have done that. Personally, I like the idea, especially since the tailgate with the embossed Ford logo (small bed) appeals to me. But a true AA bed (ala Walton's '29 AA) is its own animal and is closer to the '26-'27 TT express bed. The AA frame is angled, wider at the back than the front. The TT bed is parallel, so it's not a perfect fit on an AA frame. Some people adapt to fit. I want to put a AA express bed on my '29AA but they are rare and pricey when available. A TT frame was available a couple of years ago less than 15 miles from my house. They wanted $700 and I kick myself for not pulling the trigger. Now I'll have to fabricate an express bed, trying to emulate the original as best I can. That's for another day.