When did PSA begin adding the "gray back" identifier to their flips?
At least 10-12 years ago. https://forums.collectors.com/discussion/comment/10122895#Comment_10122895
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Comments
At least 10-12 years ago.
https://forums.collectors.com/discussion/comment/10122895#Comment_10122895
CDsNuts, 1/9/15
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