I have a JP and it is exactly the same as yours. There is no post there on the left hand side and there appears to be a pre-drilled hole for it. I'd always felt however that there has never been a post there, otherwise I reckon the hole would be bigger.
I'd often wondered if there should be a post there and had considered asking here, but never got around to it. I agree, it is can be easy to lose the ball down that side.
It might be interesting to hear whether or not any other JP owner have a post there (and what part number it is so that it can be ordered).
Cheers,
Steve (too)
