Go to your Eclipse installation then look in the "plugins" directory for
com.surelogic.sierra.pmd_* and com.surelogic.fb_*
To be concrete in the 5.7.0 release to get the FindBugs version look in \eclipse\plugins\com.surelogic.sierra.fb_220.127.116.11510021700\com\surelogic\sierra\tool\findbugs directory. There will be a file called FindBugsToolFactory.manifest which contains text. In this text is the line
which indicates FindBugs is version 3.0.1.
PMD is similar, look in \eclipse\plugins\com.surelogic.sierra.pmd_18.104.22.168510021700\com\surelogic\sierra\tool\pmd directory. There will be a file called PMDToolFactory.manifest (and one called CPDToolFactory.manifest) which contains the lince
which indicates PMD is version 5.3.3.