Does Sun Disc no longer count itself for its Legion effect?

Sun Disc has never counted itself toward its own Legion effect.

According to Rule 812.1.c, for a Legion ability to be active, a card different than the one with the Legion ability must have been finalized on the same turn.

Additionally, Rule 812.1.b.1 clarifies that Legion is functionally short for: "If you have played another card this turn, this card gains [Text]." Because the rule specifically requires playing "another" card, the card with the Legion ability itself does not satisfy the condition.