The original ‘73-77 hood is a slightly different design/shape on the front edge than the ‘78-‘80, but later hoods will fit. In ‘81 they made major changes and the front clip and hood is different.
There are several sources for aftermarket hoods, but AFAIK they will all have the later shape. I have one on my ‘75 and it fits fine, but if you knew squarebodies really well you would know it’s not completely correct.
When you replace it, make sure you install the reinforcing braces on the sides where the hinge brackets mount, and that you keep the hinges lubricated. There is a notch in the hood bracing to allow it to fold in a crash, but it will also bend/fold if there is too much strain when closing the hood. Push back toward the windshield at the same time you push down on the hood to close it.