They notoriously do not have the source code. Because the studio lost it after having told a few of the top devs to delete their copies.

One of them may not have listened, but it's unclear as yet what survived.

As much as I would love that, I think the original games being remastered to remove any bugs or maybe just having balance/difficulty changes/updates would be enough for me.

On a personal level, I would absolutely not buy a Fallout 1/2 remaster that changes how the NPC faces move when in the dialogue box thing with them. That almost uncanny valley like facial movement is something I absolutely love in older games.

The only Fallout games worth playing.