Not recommended unless the maker says it is OK to do.
NO
Depends on how old the revolver is.
The mfg. Says yes you can
Yes. Shooting a lot will accelerate wear on the gun, but occasional use is OK.
Yes, you can but it is NOT recommended. Only shoot +p ammo in .38SPL guns that are marked as +P.
As long as the +p is SAAMI approved ammunition
You must call S&W and ask.
To my knowledge no .38 Special was ever rated for plus ammo. While the gun may not explode you may damage it or cause extensive wear.
Contact the manufacturer for a correct answer
A ".38 +P revolver" is simply a .38 Special revolver which is rated to fire +P loads. It's still a .38 Special, and the +P doesn't change the dimensions of the round itself.
You need to contact S&W for a correct answer.
No. It's not rated for +P ammo. The 649 is, though.