72 Factory Radio fix?

Did the new speaker have a whizzer cone at the center?
It's a separate little stand up cone within the main speaker, of thinner hard paper and a free edge, designed to reproduce high frequencies better.
You can add them, then reglue your top screen fabric.
I have added them to many speakers for improved high response.

Basically, you cut a big-holed doughnut out of stiff hard paper.

Then you cut a chunk out so it's a "C",
that when you make the ends meet it's a funnel shape where the bottom meets the main cone. Then attach with super glue,
while adjusting to a 45 degree angle.
Much imagination or trial error to get the ratio right.
Wort the trouble.