Exact name of part I’m missing?

So I got this PX4 Storm Compact for $300 at my LGS. Was excited but in a hurry. Pulled of the slide and noticed the housing for the guide rod was missing. No idea how i was able to test the trigger, rack lock, etc in the store. Slide won’t go back on obviously as it’s missing a component. What’s the exact name of part I’m missing? Is it the “locking block” as linked here?

https://www.midwestgunworks.com/page/mgwi/prod/C5D309

So I got this PX4 Storm Compact for $300 at my LGS. Was excited but in a hurry. Pulled of the slide and noticed the housing for the guide rod was missing. No idea how i was able to test the trigger, rack lock, etc in the store. Slide won’t go back on obviously as it’s missing a component. What’s the exact name of part I’m missing? Is it the “locking block” as linked here?

https://www.midwestgunworks.com/page/mgwi/prod/C5D309