I dispute they can be brought back to original. They are only original once. You can restore it to stock configuration but you can't restore it to original.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.