1969-1970 O-Pee-Chee Hockey

I have a lot of 69-70 O-Pee-Chee Hockey cards. Some cards have the stamp on the back. Does anyone know whether this affects the price.
Thanks in advance.
Mark
Thanks in advance.
Mark
0
Comments
If these are cards ready for PSA, then it greatly affects the price, because PSA will not grade them.
If you are looking to sell to a Canadian raw set collector, then the price is not affected one bit. Some prefer
the stamps on the back. Some prefer no stamp.