Yes, it will help. I did interviews at XJ while we were hiring pilots during the last wave. When somebody applied that had also threw bags, we were able to speak with that person's manager and get a good idea of what kind of worker that person was. Usually it was a good internal recommendation, but occasionally it was a negative recommendation (ie...called in sick a lot, late for work, hard to get along with).

If you do take a job throwing bags, show up every day on time, try to make friends with the right people, don't be annoying or the "over the top" geek, and it should work out good for you.