There are 3 x different label / vinyl variations of the stock single, all released at the same time but from different pressing plants. This variation is easily distinguished as it has the VK number at 9-0-Clock (The others are at 7-0-clock) Label credits Ruben And The Jets spelled incorrectly as "Rueben And The Jets." On the B Side, part of the Matrix Number (BIZ 1-1-B) is crossed out.
The 1968 line-up of 'Ruben And The Jets' was another name for Frank Zappa's 'Mothers Of Invention' and an album was released in December 1968 called "Crusing With Ruben & The Jets." Altho' both tracks are the LP, the single has a completely different mix of both tracks.
Side A is in Stereo, and is the Stereo album version of "Deseri" but the vocals are on the opposite channel.
Side B has a unique Mono mix which is about 4 seconds longer and has louder guitar and background vocals.
'Cruising' With Ruben & The Jets LP was only released in Stereo in the US (Although with assigned Mono cat. numbers) and the UK Mono pressing was just a Stereo fold-down, so Side B of this single has the only "real" Mono mix of a Ruben & The Jets track.