I went to a website called Ultimate70s.com. I dug up this information.

January 3, 1970:
Season 4, episode 13
With Marilyn Maye.
A musical salute to the months of the year. Lyn Duddy and Jerry Bresler, writers of the music and lyrics for "The Honeymooners", wrote 12 original songs acclaiming each month of the year.

January 10, 1970:
Season 4, episode 14
With Milton Berle, Alan Drake, Jackie Gayle, Irwin C. Watson.

January 17, 1970:
Season 4, episode 15
With George Burns, Morey Amsterdam, ventriloquist Aaron Williams.
Burns chatters away about Jack Benny in one spot, and merrily sings and spins yarns about a party at Edward G. Robinson's in another. Art Carney has a ball playing Ed Norton in a sewer skit without pal Ralph Kramden.

January 31, 1970:
Season 4, episode 16
With Jack Benny, Earl Wilson Jr., Sonny Sands.
Highlights: a song-and-dance number by Art Carney to "Steppin' Out With My Baby"; a comedy routine from Sonny Sands and a ventriloquist bit from Aaron Williams.

February 7, 1970:
Season 4, episode 17
With Milton Berle, Rodney Dangerfield, Timmie Rogers.
Gleason and Berle talk about space flights with "Dr. Jerome Collins", and they also team up for a musical-comedy reprise of historical events. Art Carney sings "If I Were a Rich Man".

February 14, 1970:
Season 4, episode 18
With Milton Berle, Lou Marsh, Tony Adams, Bob Melvin, Sonny Sands.
A Valentine Day frolic. Berle and Gleason exchange gifts -- and barbs. Then they team in a musical salute to vaudeville greats.

Other than the January 10th episode and FEBRUARY 7 episode, these episodes haven’t seen the light of day. I wonder if he has them based on the descriptions that he typed. I doubt it that he got them from TV guides as well as his memory. I tried contacting them but no response.