Is my ripping technique bad

[ZetTheLegendaryHero]

Ok so I am trying to rip resources from a NES game called Arkista's Ring. To get the right palette I converted it to a gba rom, using one of the programs in the link below.

http://emu.gbxemu.com/nes/

Then I ripped the tiles and maps using visual boy advance. Finally I edit them to fix any minor errors that visual boy has when ripping. So my question is, could this techinque produce a bad rip?