Then please tell me what the difference is, because I can't see it.
The braids that go around the bearskin hats and the red crest on the side of them (this goes for all classes of the unit), and the officer has a bedroll around his torso. the musician doesn't have the gold buttons around his coat and has white pants instead of blue pants. and the 2e's flag doesnt seem to have much showing on their eagle. Including the blue design on the 2e is more of a navy blue than what the 1er has.
The white pants with no gaiters are summercampaign trousers and the blue ones are winter campaign trousers. As for the difference in the blue colour, artist impression. Trust me, every single unit of the foot grenadiers of the Imperial Guard had the exact same uniform. I honestly don't see why this would warrant a reskin, but if you really want to do it, then it's your choice.