Unfortunately it's common with the GS OTA's. I created a thread about it a few weeks ago:
Rust Spots on OTA
It's a GS problem, not an Andrews problem, or a Bintel problem, or whereever you got your scope from.
In the thread I linked, there's some suggestions about what you can do about it. But short of stripping it back and re-painting it completely, it's something you're going to have to live with I'm afraid.
I've learnt to live with the surface rust spots on mine.. it doesn't stop my wife from nagging me about it occassionally, but I know it's just cosmetic and it's not hurting the performance of the scope at all.
Maybe you should edit your thread title to remove Andrews from the title, because as I said it's not a
retailer problem.