I'm no expert on micarta but I do know some are polished and some aren't. Some are oiled (WD 40 is popular IIRC) and some aren't. Polished micarta is more glossy and unpolished is more "unrefined" and hazy looking. Oiling can darken them too.
If I had to guess, I would say the top is polished and maybe oiled, bottom is unpolished with no oil. The lighting could effect it tho too. Same knife? Looks like it.
Someone more experienced will be along shortly. Hopefully I didn't make a total a$$ out of myself with this answer.