@Debbie65 I doubt Hermès still has dye batches of Grany considering the colour hasn’t been produced for about a decade. Even if they do, there are several dye batches made of each colour, so the likelihood of them not only having an old colour but also the exact dye batch from when your bag was made is pretty slim. However, they should still have a record of the dye formulation ratio, so it shouldn’t be difficult for them to make a very small amount of paint to cover the stain on your bag.
Keep in mind, though, that even if they are able to make a small batch of paint for the stain on your bag, the rest of your bag has probably undergone natural wear over time (oxidation, dirt, oils from skin, etc.), so it still may not be an exact match. This is part of the reason Spa tries to avoid touching up/painting over damage to the body of the bag, whereas corners or edges are much easier to repair because touch-ups to those areas are less noticeable. Hoping everything turns out alright!