Hmmm, I wonder how I could fill those holes. I want to first get it shooting good, then have it Hard Chromed. Do you think that the finishing company could do that before they do the Hard Chroming.Filling holes in steel isn't very easy, and it usually costs far more than it's worth.
About the only way to do it so the holes are not noticeable is to weld them up then precision surface grind the slide.
This can damage the heat treating of the slide.
Most platers don't offer gunsmithing at that level.
To get it done, you'd have to find a crack pistolsmith/welder, then send it out for plating after he reworked the slide.
One option is to install some Brownell's dome-head plug screws.
These will give it a more "finished" look then the current screws, and will be FAR cheaper.
www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=18693&title=POSITIVE+STOP?%20PLUG%20SCREWS