Which head style you want ?

An early 70 could have been using the smaller 1969 and older screws .

Avail thru a multitude of vendors
OR get them direct at ( fyi, They have a $35 minimum order though. )

I have a pretty good amount of the 69 and earlier style( top ones ) left over from when I carried them. But not the later versions ( bottom ones )

http://amkproducts.com/