Original model in my opinon is too tight for the PCB. Changed it to have a slightly looser fit (pi_case_bottom_mod.stl).
Additional case version (pi_case_bottom_mod_rev0002.stl) with one post removed for PCB revision 1.0, as my board revision (0002) has some diodes on the back, so the PCB would not lay flat. Does also work for newer board revisions.
The author remixed this model.
Original model in my opinon is too tight for the PCB. Changed it to have a slightly looser fit.