How are guys matching factory paint ?

I have a 73 Dart that is a Y4 gold. All metal is mint with exception of one little section behind driver rear wheel on quarter panel has very minor rust/paint bubbles that I can easily fix. I believe the paint on it now is correct color. As I found places of original color up under roof drip edge. The color is actually a beige or almond appearance and nothing like a real gold color. I see a lot of Darts on line painted this exact color.

I have an automotive paint store nearby that can photo match paint. But, I have absolutely nothing I can remove from the car for them to match the color and the car won’t be registered for some time. What has worked for you guys along these lines ? I only want maybe 1/3 to f a quart for that section and some touch up spots. Telling these paint shops the paint code usually doesn’t work.