^^Yup, just for visual purposes..the GM is thicker and has more gold pieces inside. GM
The only size difference is the new "small" size they introduced with the Pomme and Transparent colors. Otherwise it's a standard "medium" size.
Also as far as colors, the beige will be hard to find now, not available in the store. I just got mine from a reseller so I think that's the route you'd have to go.
I have both of those bracelets, too, and love them so much! The rose PM is my fav because it doesn't have the 'LV' charms in it. Very understated. From my understanding the yellow and rose PM bracelets are the only two that are wider than the current PM version.