If you are trying to change your font version from stable (1) to Beta (2), then you'd have to flash one just like you do resources.
But if you're talking about changing the number '1' in the resource, then my answer is, 'No you can't' You can't change number images in the resource. Those images are of 1 bitmap. So, if you change the color, the resource pack will fail. And if you want it to work, you'd have to edit the JSON file. But that's too risky-not recommended.