Back in about 1997 they came out with this idea that all handguns need to meet certain safety requirements. Without boring you of the long list of requirements, guns have to be tested so that the can make a "roster" of "safe" guns that can be sold. The short story from what I have heard is every manufacturer has to supply a number of any particular gun to the state to be tested and approved for sale, at a considerable cost. Glock was unwilling to change or modify any of their "safe action" pistols in order for them to "approved". Although they are on the roster (because many police departments have them and use them as duty guns), they can only be sold to police\military through an FFL. No civilian sales unless it is post October 97. (So that would be Gen 2 Glock or prior) You can sell them through private sales. I have heard this same story from multiple sources but it could all be speculation. It would make sense for this state though.
I do know for certain that no FFL sales to civilians and private sales are ok. October 1997 and prior are "grandfathered"
I do have a Gen 2 Glock 19. Very picky on what I feed it.