No, clearing or editing history partially does not exist for K-Meleon at the moment.
If You use a special profile You can only set the privacy plugin not to clear history. You would then clear histroy on demand via the button on history bar.
Tools > Privacy > Settings > will give You access to details of Privacy plugin.
BTW. all data that are written on hdd can be possibly recovered and revived by others later, this is particularily true for Windows Vista which creates "shadow copies".
For info about forensic reading of
history.dat later You will easily find links.
p. s. History.dat is in a complex data structure called Mork, only on older K-Meleon untill 0.9 that had history.txt You can easily edit that as simple as with an normal editor.