Intermediate Cranking
You could remove the connector and clip a multimeter lead to the BAT terminal, and the other lead to the ST terminal. Turn the key to start and jiggle it. The meter should read zero resistance. If not then the switch is faulty.
'67 but I beleive '68 is very similar
Remove the key cylinder. IIRC the little pin to depress is to remove the cylinder. No need to
take the cylinder apart unless you have to.
There was an option for a lamp in the bezel in '68. I don't know if that will need to be removed first.
On my car the original wiring and connector were in very good condition except the accessory feed. That probably had been damaged by the power needed for under dash A/C that was on the car from around 1970 to 1990.
Expect yours will be fine but always worth inspecting.