Is it a sin to modify an antique cast iron griddle?

I inherited a cast iron griddle that was my Grandmothers. It had four spots fairly clean where she made pancakes and the rest of the cooking surface was a thick black burn on from years of use. Not knowing any better I took it to work and bead blasted it back to bare metal. Even though I seasoned it again it wouldn't cook worth a darn for a long time. I learned my lesson!