I would have to agree that I would not trust those copper lugs.
1. Copper is a much softer metal than steel. Therefore would be more subject to wearing and obtaining weak spots.
2. I would like to see the cable penetrate all the way through the clamp so that it is pinched around the cable instead of just on the end. I can see using those copper lugs ending in a very bad way.
If I recall the ends on my stands look like they are open so that you can lay the cable in the clamp and then they get smashed down around the cable from both sides. I would venture to say that this is done by a factory machine that can put much more force on the clamping process than we cam ourselves. If at all possible to get your hands on factory replacement parts I would do it. Probably well worth it in the long run.