Can't see the site because it's down but it's highly unlikely this remake uses all the same components in all the same packages as the original. The Atari 800XL would used entirely through hole components and its unlikely all the chips are still available in DIP. So there will at least be a little change to accommodate modern packages. ( I suspect)
I follow the vintage Mac community, and there are people there remaking classic Mac PCBs as drop-in replacements with the same chips since so many boards get eaten up by leaking PRAM batteries or old capacitors corroding the traces on the board. Most of the chips on the corroded board are still good (or at least the ones that are custom or no longer made) so you can desolder them from the dead donor board in the machine you bought and pop them in the new one
