Metal lath upside down ?

It honestly makes no difference for stucco or plaster when there is
paper or sheathing behind the lath to support the scratch coat.

When putting lath on bare studs, as in interior plaster, the flat areas
should be pointed downward, from front to back, for mortar to key downward, or hang on the lath better. This reduces the amount of 
mortar that slides off an falls on the floor. The idea is to just hang the 
mortar on the lath, without putting a lot of pressure on.
This is what I learned from old timers anyway.