UK registration. Not possible to see the colour clear enough but if you want something similar try RAL6009
Any paint shops near you? Go there and look through their chip books. Find which is closest. It helps greatly to look at them in the sun. You could also go online and look at current car colors to see if anything is close to what you want. That way you'd be able to order some paint with known current formulas.
This is a list of factory Model A colors from the Model A club https://mafca.com/paint-by-year-body-style/ It has the link to the paint codes but that does't mean that that particular car has a factory color on it as it may be a color that looks very original but is custom mix or off a later model. 1931 Model A paint chip chart link https://paintref.com/cgi-bin/chipdisplay.cgi?year=1931&manuf=Ford&smodel=Ford There are a couple of Toyota land cruiser colors from 1974 that come close by looking at this chart. https://www.coolcruisers.com/toppgcocobos3.html I saw a newer Jeep the other day that had a very similar OD Green that didn't have metallic in it that looked the part. For some reason Jeeps and Toyota trucks have some pretty traditional colors in their color charts.
One of my favorite A's. Looks to be the original factory Brewster Green.....here's the build thread. https://www.jalopyjournal.com/forum/threads/model-a-hemi-and-the-six-inch-chop.969142/
The owner of that used to post here on the HAMB for a while after it was finished (have a vague feeling his name was Paul?) and I've talked to him a few times at various shows in the UK, but that was all pre-Covid, and I've not seen the car out anywhere for a good few years, so not sure if still owned by the same guy.
I've got the older MAFCA book with the actual paint chips (they are just printed in the new book). The Brewster Green chip looks much darker. Kewanne Green was the other 1930 Deluxe Coupe color. It is lighter than the Brewster but has a grayish look. That car looks to have more yellow in the green than any of the stock A colors.