DC-9 towbar is also for MD-80 series. Anyway, if aircraft comes to the airport that is a first time visit its no big deal. Of course it depends on size of the airport. They probably will park this aircraft on remote parking and then you dont need towbar. But mostly towbars are for few aircrafts of it size, like DC-9 towbar is also for MD-80/81/82/83/87/88/90, 767/777 etc.
The only towbar I've been working with that is for ONE aircraft is for Fokker-100. And is easy to use, you dont have by pass safety pin only you have switch on stairboard side beside GPU plug. And even when you forgot to turn it off after pushback, when you close that door, by pass safety pin will automaticly turn off.
BWIADCA - Nikon D100