I agree...it "looks like" chrome rather than nickle. The pics help but it's still hard to tell for sure.
Yours is a later production gun since it has a round barrel. The special order ones were octagon barreled if I remember right so you gun might be too new. I think it was an option before 1933.
This is what a nickle plated one would look like, I don't think they ever did the whole gun but anything is possible I guess.
If it chrome plated, my advice is still the same. Buy the blued screw and have it chrome plated.