There are currently no PQ-8s, and 3 PQ-8As showing on the FAA registry.
N41778 Jamieson J-1 (PQ-8A) is shown as registered to Edward Fatla, but expired on 9/30/2011.
N41781 Jamieson J-1 (PQ-8A) is shown as registered to John Beoddy, but expired on 6/30/2012.
leaving only:
N61468 Jamieson J-1 (PQ-8A) registered to Johnny Nimmons in Pattison, TX as the only currently registered PQ-8A.
I think Bill's information is correct about the PQ-8A. The PQ-8 however was certified by Culver prior to production (as the LAR on TCDS 2-559 which I believe only applies to the prototype, and as the LAR-90 on TCDS A-748). If I recall correctly the Army required that the PQ-8 be certified to CAA standards prior to their acceptance. It's a shame that there are apparently none in existence. I know of none in museums or elsewhere. The FAA registry does show categories for the Culver LAR, Culver LAR-90, Culver PQ-8, Superior Culver LAR, Superior Culver LAR-90, and Superior Culver PQ-8, so there apparently were some registered at some time in the past.
Being an aircraft produced early in WWII, I can only imagine that the majority of them were destroyed during the war, and those remaining after WWII have slipped away over the years. I have an interest in the Waco CG-3A Troop Glider that has apparently also completely disappeared from the face of the earth. They weren't even used as targets or in combat as far as I can find, and they've suffered the same fate as the PQ-8.