You can use the MprTool to check the app versions of Marketplace modules. The MprTool can be found in your Program Files > Mendix > {Choose a Studio Pro version} > modeler > MprTool.exe. Then in the tool use File > Open.. and select the mpr file of the project you want to check.
Select the module (for example, Nanoflow Commons) and you will see the AppStoreVersion:
Hope this helps. I think this should be visible in Studio Pro in a standard way, which doesn't involve creating constants/folders by the creator of the module.
or you can check the .version file under .\themesource\nanoflowcommons