On a '73+ K frame the sway bar goes though the K frame, and the mounts are just flat bars that span the saddle area on the outside of the K frame. The holes are already there, because they're actually a kind of tab that's on the K frame. These are from my '74 K frame, sorry they're not better but I was taking pictures of something else in both cases. In the second one the nut is the front end of the LCA pivot for reference.
This is a Hellwig bar and hardware (beefy plates!) but the stock hardware is actually very similar in appearance. The green indicate the mounting holes on the K frame shown earlier.