[1-9] is not an optimization over [123456789]. Internally, they are the same, the range form is just there for the benefit of the programmer.

As for optimizing it, the best thing you could do is to use perl 5.10. That will have anything you're trying to do by hand build in in the regular expression engine. In 5.10, matching /04105|04106|04107/ is as fast as matching /0410[5-7]/.