According to PSA there are "approximately 60-75 or so known (total) copies in the hobby today. Keep in mind that most of the surviving Wagners have Sweet Caporal backs.
Only a few exhibit Piedmont backs, which includes the finest example of them all."
When they refer to the "finest example of all" they are of course referring to the PSA 8 Gretzky copy (which was trimmed/hand cut from a sheet).
https://www.psacard.com/cardfacts/ba...s-wagner/18155