Urgent Help Koni STR T rear shock install

I am attempting an install of Koni STR-T shock/struts on my 01 GT. I have the factory rear shock removed, but it appears I can’t reuse the factory mounting hardware to reinstall the top mount?? The threads don’t match the factory part. I was told these rear shocks reused factory hardware. FYI, I purchased these off Facebook marketplace, so no additional parts were included. I attached a photo of the thread comparison. 57DBD663-8324-4942-83F5-7A34D35CA86A.webp
 
Just a quick update for those that are interested: I was able to successfully install the rear Konis using hardware from Home Depot (closer than Lowe’s to me). The nut size is an M12-1.25 and I used an M12 lock washer, just in case anyone else runs into a similar problem to mine.
 
Nice work and thanks for posting the solution on here!

Did you do lowering springs and front/rear at the same time? What are your thoughts on the STR-T's?

I bought the car in November & it already had the Eibach Sportline springs installed. The owner never replaced the stock struts/shocks when they did the springs, which is why I needed to (the ride was really bad). I haven’t finished the install on all 4 corners yet, doing brakes while I'm at it. I expect the car to ride firmer than it did. I also replaced the stock quad shocks with KYB gas adjust shocks.
 
Oh I bet it rode pretty rough with the stockers on. Those Koni's advertise as being for lowered cars and just being newer than the factory should be a great improvement. Good luck and keep us posted how you like the setup once you're back rolling.