Hello Museum, well that's a very nice olive drab PVD as one can see - the rarest of the bunch indeed, and nicely worn.
Of all the 510.5xx this is the one with the strongest military look and appeal to me, even though none were ever officially assigned.
For some reason or another, I think the orange of the chrono hands complement especially well with green, brown and these "natural" color rather than with the shiny steel or matt black - so definitely your watch is a winner.
Wear it in good health.
Cheers,
Fabrizio