With the exception of the tie plate connection in English Tieing Joints, dovetails in American historical timber joinery are quite uncommon, and in no way were they used for joists and purlins as in the early years of the revival. I am fortunate to have done a fair amount of of restoration work and of the few historical examples I have seen which were not part of tieing joints, none were wedged.

Lap joinery and dovetail work was more common to early English work and on some parts of the continent it remained a dominate form, namely Eastern Europe. Still I have seen nothing which suggests that lap dovetails were commonly wedged in historical framing

Square pegs were a semi common way of dealing with lift. Though I consider myself a hyper traditionalist,I would still reach for a screw because the resistance provided by it is quantifiable, and it is always a blind unseen solution.

http://www.grkfasteners.com/technical_data.htm