I've got a few SF L1's, one of them being of the same generation that you're talking about I think ...?
As you are guessing, that driver won't be worth much these days, unless you don't even want a modern 'high', just a med and long-runtime low. I will be upgrading mine, but the driver must go IMO.
Here's a pic of the most recent L1 along with the previous generation (top, still in the package), from my
L1 thread:
That longer body of the older version should house a 17670 / 2xCR123 configuration if the body (including where the driver is located) is bored out, needing a new high-current driver to be installed in the head. An extensive mod, but a good reason to shelve the original driver IMO. Does the one in the package look like your generation, or do you have an even older version (which limits your options to 1xCR123 or perhaps 1x17500).
Hope this helps?