Sorry to take the post too far in the weeds on the splines. John do you have a manual for your car? Here’s a link to download.
Service Manuals – MyMopar
Browsing through it, it does appear that the hazard switch was not in the column on a 1970. But that’s not to say there wasn’t a mid year change or what’s been done to the car in 50 years. 1970 was a changeover year.
There’s also part number manuals available too.
Resource Library – MyMopar
I’ve got a 71 steering wheel for my Demon from the horn contact to the splined face measures 5/16” like yours if that helps you.