No problem. You just need to make sure that the 3 wheels are assembled facing the proper way. You can usually tell what was touching what, by looking at the applicable contact marks on the adjacent parts.
Based on the electrical diagram of my P10, the switch has 3 contacts and 4 wires going to it. The contact with 2 wires is the High beam output (one wire is going to the headlights another one to the in-dash indicator light). The other two contacts are a) main power input from the central light switch, and b) Low beam output. So, if you want to verify that your assembly is working correctly, you need to take a multi-meter and test for connectivity between the main power input contact and the two other contacts. Either one of them (and only one at a time) should be connected through, with the switch button in either position, that's it. You will have to snap the case together, for testing it, though.
And, if you decide to get a new one, you can always find a used OEM replacement.