Yes these vertical scarfs are pegged. The timber framer doing this job, hadn't made enough pegs yet.
We were taught to do at least four in the middle long lap area. Spaced 2" off each outside edge and slightly angled towards each other.
As shown in the drawing below:



The angle doesn't need to be more than 5 degrees.
And this timber framer did make a template for laying out these scarfs.

Jim Rogers

Whatever you do, have fun doing it!