I would say no.
If you want exemplars, look through my photo bucket site. You will see many examples, every single one of which was signed in front of me, at various shows through the 1980's.
Use the main page link (
http://smg.photobucket.com/albums/v222/lordstan/)
Click on any of the following links on the left hand side
# 50yrs of Yankee All Stars
# 1982 Kmart
# Brooks Robinson Set
# Hall of Fame Heroes Compl...
# HOF Yearbooks
# Kaline Set Highlights Signed
# Mantle set
# Sport Magazine
# TCMA All Time Greats
Any of these will have Mantle sigs in them
Hope it helps,
Mark