The 2004-2014 van is the 639 platform. It got a facelift in the middle of the run, which is what the "PRE-FL" must refer to. The Metris is built on its successor, the 447 platform.
In other words, that label identifies the vent as for the early version of the previous-generation van.
The 639 and 447 have completely different sheet metal, so I'm not surprised the vent doesn't fit.
It looks like you could move the pivot point and possibly trim the diagonal piece to make it fit.