Scratch that if you are hoping for the actual sheet music. I went to the "Browse the Collection" tab. Scrolled down & clicked on Box 75 - Victor Herbert 1910-1920, but it doesn't work. Apparently the site just listed what they owned (& maybe the covers). If you can get to Johns Hopkins University, I suppose it's useful for serious researchers, but not for the rest of us. <SIGH!>
Like a library, the Wayback Machine feature doesn't create the material, just produces what is (or in their case, was) out there.
I tend to use the most recent date available in the hopes of it containing the most information. In this case I later checked the first posting and think the site is less useful for us than it originally appeared.