It is possible. Here are two ways:
pom.xml on GitHub
You can tell which version of pom-scijava is used for a given version of Fiji by checking it on GitHub. For example, for Fiji 2.1.1:
Unfortunately, Fiji does not currently report this 2.1.1 version string upon clicking the title bar—only the versions of ImageJ2 and ImageJ1 are given. But you can check the file
jars/fiji-x.y.z.jar in the distribution to infer the version from the filename. Or, you can find out the version of Fiji from within Fiji by executing the following snippet via the search bar:
From within Fiji itself
From within Fiji, you can display the version of pom-scijava upon which that Fiji was built using this snippet:
But like @imagejan said, people may have uploaded newer bug-fixed versions of things on top. We are moving toward keeping all of this fully in sync on the Maven side, to minimize version skew. But we need to do it in a way that will continue to allow plugin developers to make rapid releases.