No. The converter reads the data which is already in the filenames but does not add anything. You may have noticed that you have to specify a mask to structure the filename so that the available data ends up in the right tag. How would you like to specify that your comment is supposed to be added to the comment field?
Now then, but there is help on the way and many ways lead to Rome.
a: after the import of data from the filenames use the tag panel to fill the comment field for selected files and press save.
b: See the FAQs /t/967/1 to add a comment to an already existing comment.
c: (this one is a little strange) After the import of data with the converter "Filename - tag" export that data again with the converter "tag - filename" but add to the mask your comment. Write the filenames and then re-import the added data in the correct tag field.
Please note that you do not have to import all data into already filled tags if you use the pseudo variable %dummy%.