They will match the color based on existing hair and skin tone.
They'd need to be extraordinary artists to get it right with my coloring. I have olive skin and gray to white hair. This would be a big challenge.
For many years, I dyed my moustache. Anything darker than dirty blond made me look like Poncho Villa.
One thing that's a positive is the price. $2,000 to $3,000 is peanuts compared to what a lot of folks spend on haircuts over the years. And if your talking about a decent rug, plugs or scalp reduction, this procedure knocks those out of the park, cost wise.