Brain listed where to start.. Onc stripped and dried, the scales can be ironed down with a warm clothing iron. Any that continue to curl can be sealed dwon with a spot of super glue under the curled edge and a quick touch of the iron on the scale not touching the glue.
Then seal with lacquer or shellac.
Here is one that was done in Florida many years ago with a polyester resin body.. wen through a fire the only thing the man salvaged from his house.. I did the steps as listed about,, and this is how it turned out..

The old man was super happy, the fish did not look this good the firswt time it was mounted..
Just take your time and do it right.

Here is another I restorded this year, filled with sawdust... First mounted in 1979 . So if you take your time they can be better than ok and why better than the were..
I use Citric Paint remover it is easier on the mount. Its not abig deal but can cost as much and a reproduction... Great prodjects do do and fun to see the end result.