Welcome to the forum, and congrats on the BE ...I love the rounded feel of those!
I hate strap locks ...and on an acoustic even worse. The simple solution for a tight-fitting strap on the ES endpin is this:
1. Apply just a few drops of water to lightly wet the area immediately around the strap hole (I presume this is a leather strap?) ...both sides of the strap.
2. Take a couple of nickels and put them on either side of the hole in the strap, right where you dropped the bit of water.
3. Clamp down on the nickels with a vise (or vise grips) overnight.
4. Next day you will see that the leather part where the nickels were clamped is nice and slim, allowing it to slip right into the groove of the ES endpin perfectly. I've done this to three straps, and it works perfectly and permanently. No fuss, no additional doo-dads to buy, and best of all no additional points of failure: your strap will hold securely.
Now go post a pic of that beauty, will ya?!

Edward