The early 700s, about the first 10 years, used stainless barrels on the magnum calibers, in about 1968 they changed the shape of the safety lever to the present round knob instead of an oblong one. Well worth the money.
Until recently I had a 300 mag from the mid 60's. It definitely had a stainless barrel that looked blued. Remington copper plated the SS and then treated it to look blued. It was a durable treatment since it still looked good after 45 years of hunting.