Can't see the entire tang in your pictures (Mr. fingers!)
Looks like saw blade steel repurposed. Good material.
Drilling a hole in it means annealing it first and rehardening and retempering after. Or a heck of a drill bit. Annealing could be done in a fire using ashes as insulation to slowly cool in. Or perhaps buried in sand under the fire and letting the fire fade/cool overnight.
If it had a hole on the top rear I'd guess 18th century clasp knife. But who says it needs a ring?
Some had a short tang extended on the top rear to hold pressure on in use. But simply cut away from you to keep pressure on it and not have it fold.
Being a non factory knife the builder had lots of design options.
Your tang seems by a guess to be so short that the knife did fold.
A longer tang would hint elsewise. It's strength allowing other handle ideas.
A hole the opposite side from the existing one could be used to stagger a pair of scale pins/screws/rivets. An old design I've seldom seen.
Yes single pin examples exist too but not in the position yours is in.
Your hole's example being so close to the edge hints of something else going on.
