Where to get Bracelet screw?

[RedwinGV]

Hi Folks,
I own an Omega Seamaster AT, 231.20.39.21.06.001
This one comes with screwed bracelet links.
When I got it, I had 1/2 link removed after about a month of wearing it. Well, I'm thinking I'd like it back on.

I thought I kept the pieces, but when I took it on to my watch guy, one of the screws was missing. Strange, since he gave me the pieces last year when he removed it. I never bothered to check if the screw was in the little bag or not. My fault. And, since he's not an AD, he says he can't get the piece.

Sooo.
Do any of you have an idea how I can get one screw? Even though it is a SS/Red gold, the screw is stainless. I haven't tried calling an AD in. I live at least a couple of hours from one- but that may be option

Thanks for any light anyone can shed on this.