If the car has been repainted it may be difficult to find a good example of the original color - but it all depends on how they prepared the car. On a special order car I recently sold a nice section was found behind the rear back up lamps- seems that just masked around them when they shot the car. Similar things might be found on your car :
Behind exterior door handles, mirrors, back side of front headlight surrounds, under seals or weather strip in the door jambs or under the interior - but be sure you find a strong area of paint since where ended up there was often just overspray.
Another place that has worked for me is the door jambs if they didn't sand (they often don't) the surfaces. You will find the newer coat will lift and chip with little effort.
Just some possibilities