A barn I am restoring has english tying joints. But the way it is pegged is different than any described/shown joinery in the books that I have read.

There is a peg thru the teasel tenon and tie beam as expected. But there is no peg thru the rafter tenon and tie beam. Instead of this normal peg, there is a larger 1-1/2" to 2" peg inserted vertically down thru the rafter and tie beam. How common is this? Please see attached picture. Thanks.