Several points:

[1]Rebel Yell and W.L. Weller are no longer produced by the same distiller, and haven't been for quite a number of years. Both once belonged to Stitzel-Weller, which ceased operation as an entity in 1992. Rebel Yell now belongs to David Sherman Corp. in St. Louis, which does no distilling, but also does not pronounce from where they buy their bourbon. The Weller brands now belong to Buffalo Trace (formerly Ancient Age). So, there would be no label mixup. However, if you've been drinking old Stitzel-Weller bottlings, the current ones surely will be different.
[2]Since ALL bourbons, by law, are aged in charred oak barrels, that charring imparts a 'charcoal' taste, though certainly it varies from bottling to bottling.
[3]The current Rebel Yell still retains a wheat-flavored (as opposed to rye) mash bill, but since DSC does not say where it's distilled, there is no way to know if it's the same as S-W formerly used. Even if it were, the different distilling equipment/process would impart a different flavor.

A friend of mine just found a bottle of Rebel Yell with a 1974 copyright on it's label. I know that's not much information, but it was found in the basement of a man who died at least 20 years ago. This bottle looks like it was just plucked off the liquor store shelf. Perfect bottle, perfect lable, no evaporation.  Should we drink it, or is it worth enough to save?  Thanks for your response.