Yes it will change the modification time but I don't think that really matters, given the logical reason for checking if you can write to a file (in the context of a DBM module) would seem to be that you do *actually* want to write to the file. I have not checked to see how it is being used though.

You could always stat the fh before the print (to get the atime and mtime) and then use utime to restore them afterwards although this is not reliably portable.