Not light green in colour, is it? Might be a P2.
Though probably not applicable in this case, a word of warning to any considering dismantling aircraft instruments. Those of earlier vintages did not have internal lighting and radium or other similar radioactive self-illuminating compounds were used on the instrument faces. There may be a risk to health if one dismantled such instruments in other than controlled conditions. I definitely would not keep one on my bedside table!