Hi Thai,
My brother and I grew up in Vietnam, so the A-1 Skyraider was near and dear to our hearts, my brother being an A-1 aficionado much more than I am. After I told him about your A-1E project, he was very enthusiastic but soon started to point out a few errors:
1. The airplane in Riverside, CA which you inspected was an AD-5W with its radar radome removed. Its underbelly is different from the AD-5, the latter being flat and carrying a center pylon.
https://images.app.goo.gl/YXC6Swq77c5Bt3pJA
2. The shape of the fillet of the vertical stabilizer is different and there should be no crease on the vertical portion of the stabilizer.
https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195821/douglas-a-1e-skyraider/
We would like your first baby to be as perfect as you could make it, so I hope that you would not mind our input.
Tim