I would agree this seems the way to go. I like the idea of using the snap together pins to "locate" the correct position of the part, along with placement of liquid cement on the seams to make sure the parts are bonded tightly together.
However -- one problem that might exist with this approach is there would be no way to "test fit" the parts before applying the cement, because it seems that once the parts are snapped together, it would be difficult to pry them apart without breaking the pins, or worse, cracking the sytrene in the process. So you'd have to just go on faith that the pins and notches will align properly.
-Kizzy