i think you meant to say this:
"some times in `rpg_tiles.png`, specifically these ones
look like rpgmaker 2000 tiles"
in which case you're right, they have the same structure, and the wooden plank one in particular is just a visually cleaner edit of such a tileset. the others are just a result of using tiles i already made and putting them into that same rpgmaker tile orientation (3x4; 3x3 of border grass, inner dirt, etc; 1x3 tiles above)
correct me if i'm wrong