K frame modification ?

Some '69 cars came with a K frame that worked with either anti-sway bar. I had a late '69 K in the my shop for a bit and at first it threw me for a loop. It had the cut outs and the stamped portion for the late model anti-sway bar but it also was drilled on the front lip for the early style sway bar. I guess the K frame mfg started the change over early so they could use up all their inventory.