This would be a difficult task to do generically so I think you are unlikely to find an off-the-shelf solution. While you can get a list of files accessed from the logs and compare that against the list of files in the relevant directories, you then have to account for any files that are accessed by:
server.transfer
server.execute
#include
- server-side
<script>
tags
- probably a number of other things - the above list are just the obvious ones that spring to mind for "classic" ASP.
and so forth. For some apps there can be many file that are used by the scripts but not seen in the web server logs because of the way that they are referenced.