SB K-memb Decode!?

Hey all,

I'm a little confused here. I have a 70' Duster and am redoing the bushings and converting the steering from power to manual but have run into a road block.

The K-member in the car has front disc brakes, which is making wonder if it's a later K-member.

I have the manual steering pump but the idler arm seems to be different. (I know there are two different orientations for 67-72 then 73 and up) but i'm not sure which I have.

I have the number (905M441) off the K-member casting. Can anyone tell me what I have?