Indeed not rare in comparison to a Bowden spaceliner, or Bluebird, lol. Yet compared to a Black Phantom, Sting-ray, Cruiser 5 and many others The Deluxe Cruiser is, by far, more difficult to find.
However, moreover, it's just a chain guard that makes the difference and just exactly what minor change Schwinn did in their Springer (cheaper lower quality welding on fork crown ) approx. mid too late 70's to about 83-4, but not the same as the mid 90's..
As far as the rear mount goes, it's a hit and miss deal, some regular cruisers have em and some don't. Potentially like mrg said 'around 1980-81'. Personally if I had it, I'd rather not have the caliper mount bracket type as, it's more correct than one with it.
Don't date your bike for the frame numbers, date it with the numbers on the badge, 'Julian date code' which is likely gonna tell ya it's an 80.