Owning both a Porsche 914 and a Vanagon, I feel qualified to comment on
the orientations the VW flat-four engine has assumed over the years in
its various applications. (BTW, the engine works well whether the
flywheel is mounted on the front or the back :)

As some on the List have correctly put forth, "front" is the front of
the vehicle into which said engine is ensconced. Thus, the "front" of a
given engine is whichever end is pointing to the front of the vehicle,
and not necessarily the end featuring a certain component.

In the Vanagon, the front of the engine happens to be the flywheel end,
as it faces front. Conversely, in the Porsche 914, where the engine is
mid-mounted ahead of the transaxle, the front of the engine is the fan
shroud end.

Cylinder numbering on VW flat-four engines is always the same, as is
firing order. In the offset pairs of opposing cylinders, #1 is closest
to the flywheel, irrespective of engine orientation in the vehicle. As
an aid, the Type 4 engine's sheet metal has the cylinder numbers stamped
into it, but the rule holds true for all VW flat-four mills for
automotive applications, as far as I know.

For more examples of flywheels on the wrong end of the engine, see Saab
99/900s, whose flywheel/clutch assemblies were mounted high up front
near the radiator.

Dan