1969 was the first universal draft and Sam Pollock persuaded the NHL to give the Canadiens a "grandfather clause" for one year and used it to draft Réjean Houle and Marc Tardif.
There was a draft from 1963 to 1968 where they had that privilege, but those were not universal drafts.
Basically, anyone who could lace up his skates and chew gum at the same time had already been signed to a C-Form (Orr was signed by the Bruins at age 13, for example) and were already playing on the signing team farm system (mostly junior leagues). There were a few exceptions : kids whose parents refused permission, kids who did not want to leave home for far away, kids who focused on their studies etc.
Prior to 1963, there was no draft at all.
The Canadiens spent a lot of money sponsoring junior teams and that gave them more room to have C-form signees play.
