Thanks for the link. It shows they have an armature, but when you click on the camera icon to see a picture, it shows a picture of a different item. If they can't get the picture right on the website, they probably won't send the right part.
You're right,i never clicked on the pic,but Lucky Bob's is very good to deal with,and they usually get most things right.
I wouldn't be scared of them.
It uses a Tyco timed arm,so you can probably get away with a Tyco arm.
I'm not sure how they compare on length,but it's not hard to shorten the arm if it's too long,not much you can do though,if it's too short,other then hunt up an extended goose neck pinion
If the arm is too short (shouldn't be a problem with the Mega G) you can push the shaft toward the rear sometimes with a tire press. Cut down a tyco as hornet suggested or order a replacement from racemasters. I would Call Lucky Bob's and order to make sure you get what you want.