ive seen several of the newer matte-blued or 'parkerized' Remingtons with rust right as they come out of the factory box. i was recently looking at a 700P - if theyre still parkerizing them its a sorry-ass excuse for park compared to my older 700P - with rust around where the recoil lug butts up against the action, inside the action near the barrel shank and around the scope mount threads/screws.
in the Expresses, ive noticed rust INSIDE the barrel on several different ones (new and that id bought used), around the spot where the barrel collar is brazed on. perhaps when they heat the barrel at this point it makes the area more susceptible to rust? not sure... but give that area inside the barrel a good scrub with a brush and theres a good chance the patch afterwards will come out rusty.