Most of the time darker hedgehogs have dark spotted legs, for example your hedgehog seems to be normal!
How old is your hedgie? If he is a growing baby the spots are probably just darkening because of becoming an adult hedgie. I am not 100% positive but if anything drastic changes suddenly bring him to the vet asap (ex. if he is itching, bitting, lost appetite, or changed behaviour).
I hope this helps