I took the chassis out of the AMT 62 convertible and with very little work put it under the AMT 63 and it looks like is was made for it. I cut the inner finders off the 62 body and glues them to the chassis and if fits the 63 perfectly.
Could be the dull coat, I have bought 2 cans lately of Testors dull coat that will not dry flat and I ave been using it for 40+ years and have never had that problem. looking at your picture it looks like yours has a shine to it.
I hate to say it because I use to not buy anything but AMT but now they are just selling box art the kit inside is junk. even with the discount at Hobby Lobby you are still paying 18.00 plus tax for a box of flash and warped parts. You can pay the same and get a nice new tooled kit from Revell. AMT has great selections but need to work on the tooling and QC. I will say the new tool AMT kits are great. I am through venting Happy Modeling!