Looks like a Topper 158 barrel from the contour, sights and vintage scope base, on either an SS SB2 frame or an SB1 Topper Deluxe Classic frame which is matte nickel, I don't think H&R ever made an SS 30-30 barrel, they did make some electroless nickel barrels tho, and it could be painted even, I bought a 30-30 barrel on ebay once that was said to be stainless, but it was just a good french gray paint job. Do the last three numbers of the frame serial number match the numbers engraved on the left side of the barrel underlug?
Tim