It is QS. Sounds great, too. It was the only LP quad release.It's in Mark Anderson's wonderful Quadraphonic Discography on this page (he apparently has some Q8's also):
*edit- but it says QS not SQ
http://www.surrounddiscography.com/quaddisc/quadpall.htm
JAMES LAST -
Beach Party 5. Polydor Q3811 250 (Q8) [Canada]
Happy Hammond. Polydor Q3811 194 (Q8) [Canada]
Non Stop Dancing 1974. Polydor Q3811 228 (Q8) [Canada]
Non Stop Dancing 2. Polydor Q3811 246 (Q8) [Canada], Polydor #unknown
(Q8) [Germany]
Voodoo Party. Polydor 2371235 (QS) [Germany] {Unmarked Quad}