FWIW, PSA would probably give you a free reholder and new cert# if you sent them an email with the heading "Mechanical Error - duplicate Cert number" because 12345678 in their official database is a 1989 Gary Sheffield rookie card.
ITEM INFORMATION
Certification Number 12345678
Label Type with fugitive ink technology
Reverse Cert Number/Barcode Yes
Year 1989
Brand UPPER DECK
Sport BASEBALL CARDS
Card Number 13
Player GARY SHEFFIELD
Variety/Pedigree STAR ROOKIE
Grade GEM MT 10
https://www.psacard.com/cert/12345678