False bottom rust / flakes

Hey everyone - I was just given a Krome Dispense (unused/unopened) false bottom for my cooler mash tun and I've noticed two things. The inside of the 90 degree nipple fitting facing the bottom of the mash tun has spots of red rust, and the top looks like it is cast metal that is coated, and the coating is rubbing off. I tested this for dead space and the water I measured had flecks in it.

I don't know a lot about metals and fittings but this is advertised as stainless - should I use this?

Thanks in advance.

I say give it a thorough cleaning with brushes and see it the rust is perhaps surface contamination and can be removed or if it the parts rust again then it might be something besides 304 or 316 SS. The second photo does look a bit weird for a SS casting.....

99% of the rust came out with some baking soda and a wet towel. All but the depressed areas of the surface got cleaner with a SERIOUSLY strong scrubbing/baking soda also. I'm curious if this is common and what it is, but I'm satisfied that it is SS with some deposit on it and that I'm probably fine to use it.

Thanks for your reply!

Beer stone?