A digital measuring calliper will be your friend here. If you do not have one, ask your local bike shop if they can help.
The thread size of a trunnion shock bolt is M10x1.0, so no need to check that.
Tolerances will be taken care of for you. For example, a 10mm diameter will come in just under 10mm, in order to slide through its mating counterpart.
If you are not sure about taking measurements yourself, ask a bike shop to help you. Measurements to be entered in millimetres and must be as accurate as possible.
If you're really not sure and need some help, please get in touch.