I have never even seen one on a Tikka T3, but I have seen plenty of them on other rifles. Some of them are near final dimension, and others are oversized everywhere, so you have room to remove material to your fit and taste. They were all neutral cast, but straight in line with the bore.
I would be curious as to the final weight of a T3, without scope, in a Boyds or any aftermarket stock, just for comparison.
The Bell & Carlson stock weighs 35 ounces.
The Tikka T3 stock weighs 28 ounces.