MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
it is in the table with printed parts on page: http://reprap.org/wiki/ToyREP_Buyers_Guide
You need both of them. Either ToyREP-PCB1-1 and ToyREP-PCB1-2 for ToyREP-PSU1 PSU cover or ToyREP-PCB2-1 and ToyREP-PCB2-2 for ToyREP-PSU2.
Reason is that PSUs are typically connected by three screws on side and the screw holders are also PCB holders for Arduino and RAMPS. So one of these L shaped parts have one hole and the other one two holes for PSU screws. Smaller and bigger PSUs have different positions of these screws.
If you won't install PSU into the printer, you can pick any of the PCB holders and print it twice.