When searching the net for some fuel injectors it became apparent that there a two different Bosch styles of injector. The EV1 injector is the older style with a slightly different electrical plug than the newer EV6 style. The EV1 uses the 0280 150 XXX p/n series while the EV6 uses the 0280 155 XXX p/n series introduced from 1996.
What I'm not sure of, is whether or not the EV1 and EV6 injectors are interchangeable (elec plugs aside)
Here's a couple of picutres:
The EV1 is the fatter style injector: