It depends on how much work you want to do. If you just want to install the grill by itself you’ll have issues. The ‘73 fenders won’t have the mounting brackets/holes you need. The ‘73 hood contour will leave a large gap above the earlier grill. The lower grill surround will probably have to be changed, or you’ll have gaps. If you do swap out the lower surround then that will likely leave some decent sized gaps to the bumper. And the hood latch panel won’t line up with the grill.
Since your car is a ‘73 though, you could swap on the ‘70-72 hood, hood latch panel, lower grill surround and the ‘70-72 front bumper. If you did that, then the mounting brackets to the fenders (headlight mounting area) would be the only difference. And that would just be about drilling the holes and adding the brackets you need.