The different Bay Window types (1967 - 1980) are basically:

1) 'Tin-top', no lifting roof, usually with some fittings inside but often found with nothing. There was a tin-top Devon conversion with a chalk lined, moisture retaining coolbox, cooker hob and sink unit and basic 3/4 width bed. It comes with either type of engine (1600cc beetle type or 'Type 4' 1700/1800/2000cc).  

2) 'Devon', early ones had a straight-up pop-top roof, some later ones called  'Moonraker' had a full -length side lifting roof with sliding mattress bases up top, and are very roomy. Most have 'Rock & Roll' bed below of varying designs, and sink, cooker, coolbox. Either type of engine. There was a similar 'Holdsworth' conversion with straight up pop-top roof, but these are quite rare.

3) 'Viking' 5 berth and 'Super Viking' 6 berth - mid-late 70's, similar long side-lifting roof to Devon Moonraker. 'Super Viking' 6 berth has a very large unfolding canvas roof with 4 beds/bunks up there, but takes a while to unfold. Layout inside main cabin is a bit fiddly/hard work with lots of combinations of seat/cushion positions and the cooker is oddly positioned at the rear. Either type of engine.

4) 'Westfalia' - front or rear hinged lifting roof (latter has more space up top), either with sliding mattress bases up top or canvas hammock, either 3/4 or full width 'Rock & Roll' below, and sink, cooker, coolbox, although some Westfalia variants have no cooker. 'Westies' have lots of sturdy cupboards.  Either type of engine.

5) 'Dormobile', side lifting shorter roof with 2 canvas hammocks, most have 'Rock & Roll' below, and sink, cooker, coolbox. These have clear fixed rooflights that suffer from leaks when the rubbers perish, as the water sits on the flat glass when the roof is down. Usually 1600 engine.

6) 'Danbury', similar to Dormobile, side-hinging or straight-up lifting shorter roof with 2 canvas hammocks, most have 'Rock & Roll' below, and sink, cooker, coolbox. Usually 1600 engine.