With the 2 sails came 2 booms, one silver and one black. I ass-u-me d they were the same, just different colours, but on closer inspection, there are some notable differences.
Firstly the gooseneck are different

Secondly, they are slightly different lengths

The other differences are more subtle. The silver one has a plastic cleat for the outhaul, the black one an alloy camcleat.
The black one came attached to the better of the 2 main sails the boat came with

I think the black one feels heavier.
The gooseneck on the black one has a larger diameter fitting that goes into the mast luff track, I haven't tested them for fit yet.
The gooseneck on the silver one is a bit battered and not entirely straight.
The black one
So, which is the best one to use? I'm not going to be racing.