There are other flaps available but the ones I clicked on only gave model numbers of vent they were designed for. No idea what the model of this vent assembly is but the louver this replaces measures approx: 1.25" W x 4.75" L, 0.25" D. It's not modeled exactly like the original but fits and works. I used PLA and it seems to be holding up fine but it's also really friggin cold right now. Probably need a higher temp material in warm climates or if in direct sun. 

Update - after a few runs of the dryer I've noticed that this louver actually performs better than the original ones. They get stuck open whereas this model swings freely.

Coffee fuels creativity!