Replacing Hobie 14 Mast Step - Did I buy the wrong part?

A few weeks ago I purchased what I believe to be a Hobie 14 Turbo that is in pretty decent shape. I go to take it out (first time sailing in years) and realize that I should have used a Mast Step Hinge kit to step the mast. To my disgust I broke off the pin holes in the Mast Step and now need to replace it. I purchased one from a Marine Store online. It looked like the correct part and it is very similar. The angle is only slightly different along the top edges. But, the main issue I seem to face is that the center hole at the base of the cup is not threaded. It appears to be a roughly 1/4 inch hole in the new mast step. However in my broken original that I took off the boat, it's about a 9/16 fine threaded hole that the large stainless steel rod threads into from below. I believe this part is called the Dolphin Striker. Did these Dolphin Strikers come stock on all Hobie14s? Is this Dolpin Striker an aftermarket? It does thread literally into the 9/16 inch hole in the base of my original mast step. I did notice on the Marine Store's website that they have a threaded mast step for the Hobie 16, but I didn't see a threaded mast step for the Hobie 14. This is my first experience with a Hobie 14. I've had a Hobie 16 in the past, but I don' know if this particular part is interchangeable.
Any help or guidance would be greatly appreciated.

The original Hobie 14 did not have a dolphin striker.

14's did not come from the factory with dolphin strikers until the advent of the 14 Turbo in the early 1980s. It sounds like you have one of the OEM dolphin strikers, since aftermarket ones did not screw into the mast step.

You can either drill/tap what you've got or exchange it for one advertised for the 16 (it's the same as the OEM 14 step). If you get the 16 step, make sure you get the most current version - beefed up rotation stops, the "chip keeper" (shallow holes drilled in a circular pattern around the striker hole) and angled back slightly to allow more mast rake.