I just maxed smithing to 100. I can't skill it up anymore correct (i don't mean potions)? Also i have 5 perks saved i can either craft dragonscale armor (best light armor) and daedric bow + sword (best bow + sword) or i can use them on my archery / sneak tree once their level is high enough.

Also i found a supple ancient nord bow... it is better then the elven bow i currently use. Is this bow upgraded? Or are there more items like this non upgraded with more damage.

To test if the weapon is upgraded or can be upgraded make sure to have all smithing perks then attempt to upgrade it, if its not in the list, you cant upgrade it.

^ Captain Obvious right here.