I didn´t remember that, in fact I bought a short shifter in March but I don´t have it yet (it´s in a cousin´s house), so I will wait for it.Maybe SNABB could help you out since they've started making the short shifter again and send these pins with their shift sticks.
The point is that the original pin is wider for a side and narrower on the other side. I used a piece of a nail and I cut it but the knob twists a lot. It´s not dangerous but It is uncomfortableCouldn't you just use a roll pin from a hardware store? If it's too long, just insert it and cut to length.
I´m in the same situation.
When I removed my gear knob the pin fell I don´t know where and I had to use a piece of a nail, but the knob turns itself.
Did you discover anything?