CarharttMen's Duck Bib Unlined Overall R01

What is the difference between brown and carharrt brown?

Are these insulated?

Is there a solid divider between the two chest pockets or will my pen just lay down in it like one big pocket?

I wear a 44 x32 in regular bibs, i ordered a pair of 46x34 carharts. the shoulder straps are very long. will they shrink too?