duplicate packages

[Mate Wierdl <mw wierdlmpc msci memphis edu>]

When I look into the /usr/doc directory, I see many packages with more
than one directories corresponding more than one version of the
package.  But rpm does not know about the early versions.  For
example:

# (cd /usr/doc; ls -d libgtop* zip*)
libgtop-1.0.1/  libgtop-1.0.6/  zip-2.1/  zip-2.3/
# rpm -q libgtop-1.0.1 zip-2.1
package libgtop-1.0.1 is not installed
package zip-2.1 is not installed

My suspicion is that there must be some other leftover files which
were not removed by rpm.  

How can I find all these leftover files directories in an efficient
way?

Which version of rpm had this problem (I did have Rh 6.2 beta
installed before having the current 6.2)?

Thx

Mate