Hi, Alpha,
There were different basic types of door used during the run of system 11 games. The early games had a door with each coin entry and reject outlet as separate parts, with holes in as required. At a mid-point, another type was introduced, with one casting for the coin entries and a single central reject outlet, making the door itself a 'generic' part. Some 2-slot examples of this have a Williams symbol in the middle of the entry casting, as on the flyer for Banzai Run, Swords of Fury, etc*. One refinement of this door was a bracket incorporated in the upper left corner for the 'door open' switch, eliminating the separate stepped bracket used with the earlier door(s)
The final games used an 'Electronic Coin Acceptor' (ECA) door, much the same as for Wpc games, though some territories kept the older door into the Wpc era
* Taxi is a special case here, with a sticker on the left side to point out the Start button, cunningly disguised as the Green light in the traffic light of the cabinet artwork.