Might be worth posting a picture. The old style which resemble the original GTB leg bracket has a very thin thread for the leg bolt. Original Bally are slightly wider. The new style that I have found have more thread for the leg bolt to screw into. They can be mounted in two ways - effectively reversed. I didn't notice the nail holes - but that should not be a huge problem - use smaller nails ?

I love the "dodgy brackets" description