Lakland used various pickups from many manufacturers during its 14 some-odd years, before their sister organization, Hanson pickups started making in-house pickups and pre-amps exclusively. Some people really dig the Fralins, and I agree they are very vintage sounding, if that's what you're after. The move to inhouse pickups phased in from roughly 2006-2008, depending on the model. I'm by no means a Lakland historian.
Early JOs can be found with Aeros, and maybe Lindy Fralins (not sure on that last one)
Early BGs and DDs can be found with Lindy Fralin vintage pickups or occasionally Darkstar pickups.
Early 4-94/44-02s have Bartolini pups and pre's
Early Decades have Bartolinis, Darkstars
Of course, you will find many mods out there with all sorts of stuff in the wild.
Others here probably know the more intricate details, and can correct any errors. This is what I have gleaned from hanging out here for a while.