Not by Johnny Gruelle.
Gullub writer credit induced per two sources.
1) Catalog of Copyright Entries 1946 Pamphlets, Leaflets, Contributions to Newspapers or Periodicals, Etc. Maps New Series Vol 43 Pt 1 by Library of Congress. Copyright Office. Books - Group II - 1946. Page 25. It states:
Gollub, Morris. Comic strips.
The chick who couldn't swim and the duckling whose mother wouldn't let him. v. 1, no. 3. © 7-16-46; A 3172.
Chucky the colt. © 6-14-46; A 2887.
Two little foxes. © 5-14-46: A 2550.
© Oskar Lebeck, Croton-on-Hudson, N. Y.
• 2) Michael Barrier, Funnybooks (U.C. Press, Oakland, 2015), which states:
Page 212:
"Gollub's first story for Animal Comics, 'Cubby and Tubby."
[It appears in Animal Comics #19. The GCD on-sale date for the issue is Jan 14, 1946.]
Page 28:
"In all cases where we supply the artist with either book character...the artist is handling the writing of the strip..." - Lebeck.
Page 31:
"After the first few episodes, Oskar left the artist-author to go pretty much on his own." - Frank Thomas.
Page 214:
"'In the early days,' Gollub said, 'I tried to write stories. I never liked writing stories. I thought it was time away from the drawing board. Noonan liked to write; he could do it better than I did...I enjoyed the drawing.' LeBeck accommodated Gollub by providing him with scripts." - Barrier.
By Animal Comics #27, Gollub had begun illustrating Gaylord Du Bois scripts, the first episode of Chuckeagon Charley's Tales. The issue's on-sale date: May 16, 1947. Gollub went on to illustrate many Du Bois scripts. But "in the early days" he tried adhering to Lebeck's old policy.
In part based on traditional verse.
Titles for this installment are: "If All the World Were Apple Pie" (1/2 pg.); "Tom Tinker's Dog" (1/2 pg.); "Little Betty Blue" (1/2 pg.); "Ride a Cock Horse" (1/2 pg.); "Rub-a-dub-dub" (2/3 pg.); "Jack Be Nimble" (1/3 pg.); "One, Two, Buckle My Shoe" (1 pg.); "The Crooked Man" (1 pg.); "Ding, Dong, Bell" (1 pg.)
Coloring page