Yes, I pick up stuff on the ground or 'hidden' in the landscape whenever and where ever I find it...
With stuff not stacking in inventory, I find that is the case for the same stuff but from different spawns... but that logging out and returning a long time later, the quality has reached a level that's the same for all, and I can then Click-Drag them to stack in a single slot in the Inventory. This doesn't resolve like that everytime, though.