Jim Pewter started his AFRTS-LA career in January 1967, presumably with #1M in flight RU 27-7. His "oldies" specialty show was initially 5-25:00 and lasted about two years. About March 1969, just in time for my arrival at FEN, Tokyo, JP, Jim Pewter was demoted to once a week at 1-55:00. I made a note of it in my FEN log when I reviewed show #366, RU 41-9 in April 1969. The Jim Pewter Show 1-55:00 lasted for about seven years (364 weeks)!
Then at the start of the Bicentennial Year, the Jim Pewter Show was promoted to 5-30:00 with (approximately) #752M in flight RU 1-76 (the first transitional quarter) in January 1976. Because of the long period of one-per-week, the numbering system was in complete disarray. For five-per-week, Mondays, which normally started with xxx1 followed by Mondays as xxx6, instead started with Mondays as xxx2 followed by Mondays as xxx7.
If Jim Pewter continued his 5-30:00 "oldies" show through the transition to Unistar/SMN satellite programming in October 1995, his final cassette-delivered program would have been (about) #5961F in flight RC 52-5, December 1995.