Alternative labels added without the "Sold in UK....." text. Imagine these to be circa 1968, although the original 6503 sleeve was still being used with this particular copy.
According to Sharon Davis's book "Motown The History" (which is quite definitive) the first U.K.Tamla Motown L.P. issued in Stereo was STML 11021 "The Four Tops Second Album" in March 1966 and some of the Tamla-Motown compilation L.P.s were being issued in Mono only as late as 1968.
With collections such as this the idea would have been to have a collection of "A" sides of the singles and often the Stereo versions were significantly different.
Did they ONLY issue this in mono? They could have issued it in stereo as so many of these tracks DO have stereo mixes available that had since turned up on other albums. The label, Tamla/Motown was launched partly to coincide with a tour of the UK by several of Motown's "premier" artists and groups in 1965.
Actually issued March 1965 in UK as lead album release of the then brand new Tamla-Motown imprint.....................6503 year and month code can be observed at bottom right rear of flip back album sleeve, printed by the usual suspects, Garrod & Lofthouse Ltd.