Hey, I just finished cleaning up a mahogany version of these purse!
As for your question, if it’s just a surface scratch, I’d consider leaving it as is. The couple of times I’ve used filler, I haven’t been able to get the paint coverage just right to “hide” the repair, making it stand out even more. My steps were to mix Angelus filler with Fiebings black leather paint to get it to a dark gray, instead of white. Unfortunately, no matter how many times I’ve tried sanding and painting over the filler, the paint just isn’t covering it as well as hoped.