Not too many people would call Jackie Wilson Brunswick releases "Motown records", nor would they refer to any of the Anna productions as "Motown". Marv Johnson's recordings leased to United Artists in 1959-1962 were written by Motown writers, produced and recorded by Motown producers in the same studios as concurrent Motown releases were being produced/recorded, using the same session players and back-up singers, and arranged by the same arrangers. While under his recording contract with UA, Marv Johnson was writing and producing Motown songs and records in Motown's offices.
Jackie Wilson's songs were written by Berry Gordy, but in no way could be considered Motown productions. They were arranged by Brunswick contractors in New York, and arranged by New Yorkers, instruments played by New York session players. "Reet Petite" was recorded in 1957, long before Motown Records existed. But, even Jackie's 1959 and 1960 recordings, recorded after Motown was in operation, had only Berry Gordy's writing as a link. Cornell Blakely's Ace and Mercury-distributed Rich records releases are much more "Motown" than Jackie Wilson's Gordy-written releases, or even non-Barrett Strong Anna releases.
Even The Spinners' "That's What Girls Are Made For", is a bit less a "Motown record" than Marv Johnson's '59-'62 releases, as although it was recorded in "The Snakepit", using Motown session players, it was produced by non-Motown staff, and written by non-Motown staff, and sung by non-Motown singers. Although Marv Johnson wasn't a contracted Motown singer while contracted to UA, he was a contracted Motown songwriter and producer, and was currently working for Motwn. None of Gwen Gordy, Harvey Fuqua nor any of The Spinners were working for Motown at that time, in any capacity, as far as I know.