I was wondering if hatchery trout will begin to look like native trout if given enough time in natural enviroments? Also given the same time, will they begin to act like natives?

Yes And Yes to your ?s
A trout has to assimilate to its new environment to survive,ie food source ,bugs,forage fish etc. The trout will change in appearance also,the fins will grow out,the color will change a bit to match the new environment.If you ever catch a holdover fish and look closely at it you can see the difference compared to a freshly planted fish.

So, the hatchery 'bows, when given enough time will begin to develope the bright pink slash like the wild trout?

Yes.