Many cars from the 1960s that pressed the studs through the hub and into the drum actually peened the studs in place. GM had a set of Kent Moore tools that allowed you to cut the peened area before pressing the stud out to prevent oversizing the hole, and another tool to peen the new stud to hold it in place. Naturally, I didn't do that on my car and I oversized the holes. I was able to find studs with a large enough knurl to fit securely. On other vehicles, I've also used a small tack weld on the backside of the hub to ensure the stud doesn't spin. Be sure to grind off any zinc plating on the new stud where you plan to tack it, and go in hot and fast with a small tack to minimize the heat affected zone in the stud.
This is absolutely the case with this car. The stud splines on the thread side look like they had been swaged wider, and I can see where pressing those studs out may have been like a broaching operation to open up the holes.
Just to give some general background, the last time I replaced a set of brake drum brakes was in the '90's. Since beginning married life in 2001 I've done a lot less car work, and where I''ve done brake work it was a disc brake conversion on a '56 Mercury or disc brakes on daily drivers, my first work being '55 Ford brakes in the late '80's.
And whatever I'm saying above, I'm just providing more detail and not being argumentative. I'm open to any ideas and appreciative of discussion here.
Truth be told I don't think I ever had to replace a front brake drum on any of my '55 Fords unless I had a brake drum with the hub installed.
Also on the table if things went badly enough was a disc brake conversion. Truth be told I probably didn't need to replace the drums, the mileage on this car isn't that high and I don't think the thickness has gone down much, and to be certain there aren't even wear grooves. Same could be said for the shoes. But one of the rear drums had a large piece fall off at the edge, so I figured it's best to just put a new set of drums. And the brake job is something my dad started before he passed and he had what seemed like all the necessary materials, so I figured he was probably just doing the whole job because there was probably a fluid leak somewhere before he started the project.