While Rafeeq suggestion is good, if the installation crashed, who knows at what stage this happened & what is valid & what is not? Does it do the Registry update last during the install? When does it update CONFIG.XML during the install process?
I wouldn't rely on the file version either. We've never had MR4 in the environment, yet there are files in the Symantec folder with a version of 11.0.400.2263
Additionally, RTVSCAN.EXE, SMC.EXE and SMCGUI.EXE are constantly running. RTVSCAN has a version of 11.0.5002.290 while the other two have version number 11.0.5002.301.
SYMCORPUI.EXE is the executeable that show the status screen when you double click the Systemtray shield icon. My client reports that I'm running v11.0.5002.333, same as the registry.
Having Windows Explorer show the file versionas a column there is actually no file that has the exact version as the Registry does.