I have used both NFM Coyote and this stuff and it's an exact same match, I sprayed two guns with each paint and it's the same (minus the IR bit the NFM has)
Humbrol No 29 Dark Brown is also a near match to Magpul FDE and very easily obtainable as a spray in the UK as a last resort (available on Amazon), you will almost certainly need to clear coat that though (suggest a satin coat).