The two studs are used to help align the plates during assembly. First the part on the lower right bolts on the block, then the two studs are threaded into two holes so that the lower middle and lower left parts can slide over the studs and maintain alignment while the 3 other bolts are installed and snugged. Afterwards the studs are removed so the bolts can be installed to finish the housing installation (a PDF of the original installation instructions is attached).
