Hello everyone

I'll be at Expos Fest in april in Montreal and i'll be able to get a lot of signatures from retired players. Do I need to have them sign an official Rawling MLB baseball? I'm in Canada and these balls are expensive and hard to find. I can't buy them in the States because of the poor exchange rate and the cost of shipping. Am I losing value if the signature is not on an official MLB baseball?
Thanks for your help
Alain