Forget I said that 
Don't be embarrassed about your opinion. Feedback is useful.
Or perhaps the store owner polishes his makeshift store counter, whichever way you want to rationalize it
That was was pretty much my take on it.
I think you definitely had it right the first time. The shine had a settled look to it with the more coarse roughness that would fit a store in the slums. I think the second one loses it's realism with how it's reflecting the light.
I am not sure there's a "more" or "less realistic" case. Today I have seen a steel pipe of mirror-like finish on a construction site, which itself was pretty dirty. The roughness is primarily a consequence of the metal finish itself, much less that of dirt and grime (which however affect the intensity of the reflections).
I would like a tone down on the highlights overall, right now it has more the feeling of polished chrome, instead of oxidated steal.
not only on the main horizontal pipe, but also the cylinder ar the back, and the reddish pipes on the right top.
I've done quite a lot of observation of metal ducts IRL, so I can try to give you an educated answer
I don't think the metal you see in my picture is too polished for being some kind of brushed stainless steel. The brushed stainless steel I showcased has significant roughness and anisotropy, I believe the scale at which we view the image (the main duct is about 80 cm in diameter) may give a false impression. Chrome usually has pretty much no roughness nor anisotropy, with very sharp mirror-like reflections (usually it's more with a smooth, electroplated finish, and not brushed with grit belt like stainless steel).
The other aspect is: stainless steel does not stain or rust under regular conditions. If it is corroded, you would see an oxide with a rather light purple color. It behaves a lot differently than cast iron or low grade steel (which would rust with the classic orange iron oxide). So in a sense, if it is not subject to harsh environments (such as acid rains, saltwater), stainless steel can only get dirty with whatever is smeared on it, not so much because of the degradation of the material itself. But that is just one side of the discussion.
When it comes to these cases of texturing, I believe the main problem is simply a matter of interpretation. What do we see in the original image? Basically we see brighter sections of grey metallic-like pipes and dirty-orange sections of pipe. There are actually various types of materials which could give that impression at low resolution, but once you get at much higher resolution and you see much details, you can end up with very different results.
1- My own interpretation was that the pipe was made of brushed stainless steel, which was painted in the more orange sections. I ruled out the assumption that the orange color came from rust, because of the area of the pipe which is painted with the "Welcome" kanjis. The main horizontal pipe is like a makeshift counter, which the shopkeeper would clean more regularly than the rest of the pipes. The pipes are only dirty because of grime, not because of rust.
2- One could interpret this as as assembly of aluminum (where the pipe is shiny metal) and rusted iron. The "Welcome" kanji painting could have had some corrosion-resistant coating, who knows.
Aluminum is fairly shiny, but generally its diffuse/glossy ratio is more than that of stainless steel, so it could have given a different result on the grey sections. If the orange is rusted cast iron, the resulting high res texture would be very different from what I've shown.
3- The pipe could be made with galvanized steel/orange-painted galvanized steel. Galvanized steel is also very corrosion resistant, but its diffuse/glossy ratio is quite higher than that of stainless steel, and it would certainly tone down the highlights on the metal. This interpretation could give a result much closer to what you suggest. Yet again, galvanized steel has a very particular grain to it.
Personally, I have to understand how the material is made of to try to replicate how it would look like. Based on your feedback, I can have a go on interpretation 3- and see what I'd end up with. I don't think interpretation 2- is valid (again, based on the painted kanjis).
Also the white of the poster feels too white, one note in CG is that there aro no absolute colors (rgb 255,255,255) best is to always keep well below that.
You're right, I hadn't taken care of toning this one down. I'll make the revision.
