At some point he
must have, or else why would he have given up everything to follow Him?
All these things did happen - but Judas did not become a follower of Christ for personal gain, since there was nothing to gain, at the time. Each and every one of the 12 gave up their family ties, their jobs, their homes, and every other material consideration, to wander with Jesus throughout the whole country of Israel. So, there must have been a spark of faith, at the beginning. Who can say how it got quenched, or even when (since it seems clear that during the last several months of Christās ministry, Judas was already out of the program, and probably only stuck around because he had no place else to go).
However, that having been said, the writer of the Letter to the Hebrews was not writing to Judas, but to second-generation converts who had gone through the conversion process, who had been taught in person by the Apostles, and who had been carefully screened for membership in the Church. Since Christianity was illegal by that time (since both St. Paul and St. Peter had already undergone the death sentence for their preaching) itās not likely that any of these people had joined the Church to make business connections, or to impress a member of the opposite sex - their faith must have been real when they made their original Profession of Faith at their Confirmation ceremony.