Even if we consider this story (or at least the "collecting otherworldly magitek") to be canon now, I wouldn't expect it to be referenced elsewhere. At best, the Ironworks have learned some new manufacturing techniques, but they don't need to specifically point that out later.
I think you're mistaken about it being delivered to the grand companies though - I checked
the script. Cid asks you to salvage the magitek parts, and the other engineer says you can hande them in at Black Brush or to their "colleagues in the three city-states", who will pass them on to Cid. Those would be Ironworks employees, not the grand companies.
Also, it occurs to me that while Noctis managed to get home, we haven't dealt with whatever is sending foreign magitek and daemons into our dimension in the first place? It's established that Noctis may have been accidentally teleported here from a Niflheim base (the evil empire, I assume?) - maybe it was a once-off that warped a fixed number of MTs across, and we're just mopping them up, but we never really get any explanation for what's going on. Even if it does clearly belong in the "don't think too hard about it" basket.