https://www.psacard.com/pop/baseball...ostcards/43382
Looks like 2 are PSA graded with the card mentioned and the autograph AUTHENTIC. If you don't see it on that page, click the tab halfway down that says "PSA/DNA Certified".
That doesn't include all the ones that were graded in blue flips with just "Trading Card" instead of the set info. Some people did that to take advantage of bulk submission groups or lower prices.
On Worthpoint, I found:
Cert 83922140
Item PEREZ-STEELE HOF
Primary Subject RICHIE ASHBURN
Grade NM-MT 8
https://www.worthpoint.com/worthoped...rez-1836030840
Cert 83483009
Item 1996 PEREZ-STEELE HOF POSTCARD 220 RICHIE ASHBURN
Primary Subject RICHIE ASHBURN
Grade MINT 9
https://www.worthpoint.com/worthoped...rez-1816994096
Cert 84069020
Item PEREZ-STEELE HOF
Primary Subject RICHIE ASHBURN
Grade GEM MT 10
https://www.worthpoint.com/worthoped...rez-1989295754
Since those are all blue flips, I would say there are at least 5 PSA graded and even more that are mislabeled.