Imponte Dukes, where are you hiding my darling?

I'm trying to round out my collection of muscle cars and so far the Imponte Dukes is proving to be tough nut to crack as it's not purchasable through SSA Super Autos (limited to returning players) and doesn't want to show itself in the areas its supposed to spawn in.

The wiki page indicates that it is "sometimes found around Rancho, Davis, La Puerta and Cypress Flats and Vespucci Beach" and "rarely spawns on the Great Ocean Highway, just outside Los Santos".

Does anybody know if this is a time of day spawn like some of the other rares or is it just luck of the draw to find one roaming around those neighborhoods or parked somewhere?