1514 - PSA MK?
Source: https://www.podbean.com/eau/pb-53mbg-1a7f1e4 Dr. Beckett responds to Mike Lach’s question about why grading companies don’t apply an MK (mark) qualifier to post-production, in-person on-card autographs. He explains PSA’s early-1990s introduction of qualifiers (OC, MC, ST, MK, PD, OF) to note manufacturing related issues, and how MK indicates extraneous markings that lower…























