Labels are not getting created in Perforce.
I created a small sample Subversion repository with only one file under trunk. I then branched that file to a folder in the tags directory. I created the exclude.map with ^tags/.* and set the config variables accordingly. The conversion run indicates:
... exclude.map: ^tags/.*
... Searching for labels...
... Branch map count:
... A:1 test_svp2p4labeltest
which seems to indicate it sees the tag. The tags directory itself is not imported (as expected) but then no label is created in Perforce.