Does having completed BLC move me to the top of the Army National Guard promotion list?

There are a lot of things that go into the promotion list. While point wise you may be sitting 40th on the list, the list is everyone in your state that holds that MOS that is an E4. If an E5 slot opens than EPS will start at the top of the list and go down offering the slot by contacting the units about it. If the person is flagged or unable to take the promotion then they go to the next person. Because the guard uses the step program having BLC done doesn't really make a huge difference except you get promoted to SGT when you accept instead of CPL. I would highly suggest you get your points up. Check with your training NCO about the points you have control of (APFT/ACFT, weapons qual, correspondence courses). You control your career.

If you had BLC complete and still came out 40th, you were probably missing points somewhere (awards, APFT, IWQ, civ ed, military schools).
That said, IF your state follows the correct policy, and IF BLC was correctly coded by your BDE, then as they go through the promotion list, units have to offer those with NCOES complete before they offer a STEP promotion to someone without NCOES complete.

Depends on your State, ask your Hq personnel unit.. They will know for sure, most others are just guessing unless they can show you a reg.