Coming clean, I am not a fan of 50s music whatsoever. That said, The Primettes, the first name of The Supremes, were locked into that late 50s/early 60s sound. "Buttered Popcorn" featuring Flo on lead is an example of why Diana was a much more marketable lead singer.
Berry Gordy had the sister group to The Primes, who morphed into The Temptations, record with different producers including Smokey Robinson, Harvey Faqua, who ironically would produce their final #1 single, "Someday We'll Be Together" in 1969, which also was the final number 1 of the 60s and Berry Gordy himself, did the honors on several songs.
Only Smokey Robinson's calypso influenced "Your Heart Belongs to Me", a song referencing the escalating Vietnam war, made any noise on local and regional Midwest radio.
But for a simple historic understanding what leaps and bounds they grew once they became The Supremes, this release featuring their early Lupine Records offerings is a necessity for any fan of The Supremes!