I noticed on a brand new rifle that there were some small spots in places like in the bottom of the inside of the receiver and in a couple other random spots in and on the receiver (of a bolt gun) that kind of looked like rust. In some of the easy to get spots it pretty much just rubbed off with a cotton t shirt but is still there in some hard to reach spots. Is this rust or maybe just oil of some kind that just looks like rust. It's a tikka t3x stainless that I purchased a couple days ago.