A good thing to keep in mind is the word “stainless.” It means exactly that – the metal stains less. It does not mean stain free.
That being said, I recommend discussing the end use with your customer. Will it be inside? Exposed to the elements? Does it need to be magnetic? When ordering from your supplier, discuss their needs so they can advise on what grade of steel would be best (304, 316, or 430).
A general word of advice: be sure to clean the surface before working with steel. Oils, contaminates, and other imperfections impair your finished product.
When CO2 lasering, use a thermal marking solution (or spray) to achieve a black mark.
For safety reasons, ask your supplier to properly deburr your order.
-Bob Shapiro, ID Plates