I would use it. Stainless steel is fine and rust is also fine. Iron is not as toxic as most people think it is. That is why if you dive, there will be more corals growing on an iron shipwreck than the surrounding rocks.
Most stainless steel contains Chromium, nickel, manganese, molybdenum and carbon.
These things are also in NSW and also in (I think) ASW.
Your 316 Stainless has 18% chromium and 8% nickel.
Of course there is iron in there also which gives it slight magnetic abilities.
Of course iron is an algae nutrient, it won't cause algae but if you have algae it will make it greener. A very small amount of iron will be released from stainless steel as most of it is inside the piece and only a slight amount on the surface may react with the water. It's not anthrax.
There has been some stainless steel in my tank for about fifty years. So far, I don't see any problems. :scratchch