In the original Star Trek series, Captain James T. Kirk had a different middle initial. What was that middle initial?

The original Star Trek series had two pilots, the first, "The Cage" was never aired as the pilot. The second, "Where No Man Has Gone Before" featured most of the cast that would star in the series over the next three years of episodes.

In that second pilot, Kirk was threatened by a character in that pilot. A grave was dug, with a tombstone marking the grave for James R. Kirk. According to the Starfleet Access commentary on the Blu-Ray, the remastering crew debated over whether or not to change the middle initial on the "James R. Kirk" tombstone to the proper "T". While some members of the crew were for it and some against it, they ultimately decided not to, due to the ridiculous amount of rotoscope work it would have required.