Several years ago at MIA, I was supposed to fly a USAir 757 to BWI. An MD-80 was substituted. When it pulled into the gate, they had a major problem with the jetway, because it wouldn't go low enough to fit the MD-80. Passengers couldn't deplane and we couldn't board. After about a 30 minute delay, they decided to use steps. They pulled away the jetway and hooked steps up to the forward entry door, and we boarded the plane that way. So in some cases, jetways are made for certain aircraft.
Fly Eastern's Golden Falcon DC-7B