They may be stress cracks and not dry rot. I've had several tires that once they got some miles on them but were not "old" developed stress cracks.Replacing my Metzler Tourance with 705s because of the signs of dry rot. I see it on your front tire as well. I'm new to street bikes. Is this not something to be concerned about?
705's and especially 244's on pavement are prone to this.