Cleaning?

[B. Dudley]

If you want a BTFE, One could be fashioned for it and the original forend wood put away for safe keeping and that way no alterations would be done to the gun and it could always be put back.
But that would only be advised if you like shooting with a BTFE. When it is on the gun, it would not add value unless it had the original forend wood with it.

Recutting checkering would not hurt value, especially if it needs to be done. And if done properly, it would improve the value if the original is worn. it could be done so that it does not look like it was touched.

If the buttplate is broken, replacing it would help it since it is something that is broken and needing repair.

And as far as cleaning. You do not want to do anything that will damage the original finish on the metal or wood. Nothing abrasive. And if the finish is original, it would be shellac. Shellac is disolved with alcohol.