The current default behavior is to simply keep the weapon at the bottom of the view, regardless of its vertical size (i.e. having the status-bar on vs. having it off). While the sprites in most existing Wolf engine games don't take this into account and must be shifted to avoid a big gap (since nothing was actually drawn below), mods may have bigger weapon sprites that look unwieldy when the status bar is on.
So the current behavior is certainly fine as a default. However, a flag in the actor definition to auto-adjust Doom-style would be very useful. I'm currently using the Jaguar Wolf 3D weapon sprites, but it looks takes up too much space when the status bar is on, as id designed them with a full-sized viewport in mind.