Is there any difference in an injected-to-Entreelink/Forest Pokemon and one who was caught legitimately during the time Dream World was active?

[JT_Diamons]

Title.

[theSLAYER]

4 minutes ago, JT_Diamons said:

Title.

No difference as long as the details inject was legal.

[JT_Diamons]

What exactly happens on injection? Are you injecting a .pkm or is it similar to a WonderCard where you're picking up or capturing a Pokemon that the game generates within itself?

[Kaphotics]

If you edit the forest directly, all you have to edit for a pkm is this:

Species, Gender, special move, how it is animated (not saved in pkm data), and if it is hidden (not saved in pkm data). The game just re-generates from the template data that's stored in the save file.

Kinda hard to screw up Species-Gender-Move1 legality.

[JT_Diamons]

So the PID + IVs generate on its own like a normal Pokemon? Would this differ at all compared to a perfectly normally caught one from the Dream World era?

[theSLAYER]

when you "receive dream world era Pokémon", this is how the PID-IVs are generated.
They have the mon in that encounter table, then you proceed to encounter it.

This is the same thing.