If you're interested go and talk to them, just be honest about your experience and the time you can give to testing.

When we chose testers for last mod we tried to have a variety of people, experienced players/modders on testing team can help you locate cause of problems quicker, but team might also like to have less experienced players to see how they cope with installation, and learning how to play the mod. Also people who haven't played TW so much can notice some of the bits of original game that you forgot to change better, whereas everyone else is so used to original game they don't think to mention it.... People that are willing to just read through all the text information and look for typos are useful too.