The back pocket will be shaped like any other 5-pocket jean and will not have exposed rivets.The last jean had exposed rivets, yours did not, so it will be a similar jean to yours with a slightly different fit.
A loomstate or even sanforized denim should be washed every 5 to 8 weeks if worn every day. The more often you wash the jean the less prone the denim will be to tears and premature cuts, like the one shown in the photo above. Best way is to turn the jeans inside out and wash them in a washing machine in cold water with some Woolite Dark or Dr. Bronner's soap. Then remove the jean from the washing machine and allow it to fully air dry before wearing.
That looks like the denim starting to rip where you've turned them up. Also, this can be a sign of not washing the jeans often enough. How many times have you washed them in the three months you've been wearing them?