Thanks guys.
Don, from your answer and pic it would appear that:
- the left and right outer ends are the same
- the left and right inner ends differ in that the grease fittings are on
opposite sides, allowing for easy access on the top side, when fitted.
Some of my spare ends are the ones without grease fittings so by comparing threads with the zerk type ends it looks like the inners are right hand thread and the outers are left hand thread.
If I've got this right, I can now mark them and I'm done.
Thanks again.