For Mac you can usually look with Finder Info window on the version of a plugin file, including the dylib files inside your built application. For Windows you can check details on the DLLs in the properties dialog, but did you know how you can check it on Linux?
For Linux all the libraries are indeed also applications. You can run them in Terminal and they print a simple message to the console:
So if you set executable flag, you can launch them and see the version. This works fine for a few years now.
[centos@ip-172-31-17-30 infos Libs]$ chmod +x MBS_Main_Registration_Plugin_19505.so
[centos@ip-172-31-17-30 infos Libs]$ ./MBS_Main_Registration_Plugin_19505.so
MBS Plugin, version 17.5, built Nov 27 2017
[centos@ip-172-31-17-30 infos Libs]$