As a truthful and honest collector...and a huge fan of the show....this absolutely disgusts me.
I wonder if any authentic versions of those cards signed by Andy exist.
By the time the cards were produced he probably really only signed his name for friends and I can't image friends bugging him to sign trading cards.
There are a number of sellers on eBay who specialize in fakes from 60s and 70s tv shows. One on particular has pumped out a ton of Gunsmoke fakes. The same seller also does cast photos and signatures of people you’d think were relatively low risk such as Don Knotts, who signed freely through the mail for decades.
The takeaway is: nothing is immune to fakes. These slugs will fake anything for a buck.