If the place that stamps them thought it would work, they would probably include it in the application. I'd guess that they are not going to work without some rework, which is common even when they are described as "Fits". If you are very lucky, a member here has run into this exact thing and has experience with it. Otherwise, your best bet is to take good, clear pictures of the whole area, take measurements and show what you've got. The part might have some dimensions or perhaps another part would work as well or better. Good Luck! BTW, this is in the OT section, but fits HAMB criteria. It might get more views in the regular section.
looks like the 53-54 flare out at the bottom, while the earlier cars curve in. Look at the car, look at the picture of the replacement part, does it look like it'll fit? or not?
https://www.curbsidecl***ic.com/aut...yleline-de-luxe-bel-air-the-belle-of-bel-air/ 53 panels https://www.ebay.com/itm/203912866496 50 panels https://www.ebay.com/itm/204408316923 Very different! Also, since they make the 50 panels, it's your best starting point.
They will more than likely not be a direct fit replacement. The 50 is 2 model designs away from the 53. The 49-50 (your design) and the 51-52 and the 53-54 (what you hope to apply) were the design points. There were trim changes on same design point cars, but the majority of the panels work. The 53 panels may work for what you need with minor modification or provide the patches you need if you aren't going to replace the entire panel.