67 specific manual steering box mounting bolts

I pulled the cast (omg that's heavy) iron power steering gear out of the dart I'm working on.

I'm putting an OEM (light as a feather) Aluminum manual gear box in.

The bolts from the manual 68 box are 12 point and have a flat maybe conical washer.
The 67 PS bolts are 6 point and have split lock washers.



My other 67 dart with stock OEM manual steering has the 6 point but without removing one I can't tell if it is a split washer or a flat washer

I can see how you would not want a split washer on aluminum as it could cut the AL away with tightening etc.

I want to use the 6 point 67 style bolt.
What do you all think / know, flat or split washer for 67 SPECIFIC manual box.

Notice the bolt on my 67 has a washer showing past the bolt. And the split does not show much but it does show past the 6 point. I can't decide how much it shows.

The flat washer on the 6 point shows a lot.

You can see (barely) the washer under the 6 point on my other 67 dart with manual steering.








I guess some engine degreaser and a pressure washer would clean it up and if push comes to shove I'll remove a bolt off my other 67.