PDs always have weird cars ordered or made availible to them for a variety of reasons. Personally, I believe there were more than 3 Hemi 4-doors built, as Suffolk County PD Hwy Patrol had more than that themselves. Grant it, it was 40+ years ago but my Dad had friends on there that frequently mentioned how they hoped they could get one for their shift or how some supervisor got one & they really didn't need a car like that. All the manufactureres did it back then so it shouldn't be a surprise & given Mopar's notorious reputation for erratic record keeping who can say with absolute certainty there WERE only 3 produced?