Were Glenn Bidmead and Gregg Allman both songwriters?
yes
Title: Win, Lose or Draw (album)
Passage: Win, Lose or Draw is the fifth studio album by American rock band the Allman Brothers Band.  Produced by Johnny Sandlin and the band themselves, the album was released in August 1975 in the United States by Capricorn Records.  The band had previously released their fourth record, "Brothers and Sisters", in 1973 to critical and commercial success.  The band toured the following year, attracting large crowds and earning substantial amounts of money, all while internal tension grew between the members.  Vocalist Gregg Allman and Dickey Betts released solo albums — "The Gregg Allman Tour" and "Highway Call", both issued that fall — which prompted speculation on the band's unity.  It was the last album to feature bassist Lamar Williams and pianist Chuck Leavell.
Title: Gregg Allman
Passage: Gregory Lenoir "Gregg" Allman (December 8, 1947 – May 27, 2017) was an American singer-songwriter and musician.  He was known for performing in the Allman Brothers Band.  Allman grew up with an interest in rhythm and blues music, and the Allman Brothers Band fused it with rock music, jazz, and country at times.  He wrote several of the band's biggest songs, including "Whipping Post", "Melissa", and "Midnight Rider".  Allman also had a successful solo career, releasing seven studio albums.  He was born and spent much of his childhood in Nashville, Tennessee, before relocating to Daytona Beach, Florida.
Title: Glenn Bidmead
Passage: Glenn Keith Bidmead (born 3 February 1962) is a Sydney-based singer, songwriter, guitarist, performer and producer.  With songwriting partner Steve Glover, he was a founding member of Australian rock band LemonJuice, which enjoyed several years of success in Japan and South Korea.
Glenn Bidmead Gregg Allman