Do you know what brand of grout was used? Grout manufacturers usually sell caulk that matches their colors. Matching the color any other way would be iffy at best.
Don't know. I have plenty of extra tiles, but no clue what grout was used. Luckily though .... whatever color it IS, it is VERY close to that generic "almond" or "bisquit" generic color that most places sell, so I am going to go with that. I did a "test squirt" on some masking tape and it will blend in nicely.