Certainly one can be brought to Christ without the full instruction and official endorsement as a Certified Calvinist. A Reformed pastor friend of mine was brought to Christ as a result of Benny Hinn's false ministry! He knew nothing of sovereign grace (nor of the true gospel, really). But he did get a sense of his own unworthiness and helplessness, guilt before a Holy God, and reliance upon a Substitute, Christ, for the rescue of his soul.