No, I meant in the "real" world. For example, did controllers say "Follow the 717" or did they say "Follow the MD-80"?
I suspect that airworthiness professionals might take exception to the suggestion that they don't live in the real world, but I take your point.
For ATC purposes, the aircraft would be flightplanned as a B712 i.e. Boeing 717-200 and referred to by controllers as a 717.