I just purchased a used Mesa 400+ from the mid 90's in excellent condition. The guy I bought it from shipped the tubes separatley from the amp (per my request), because I did not want the tubes showing up broken. All of the power tubes are Mesa 5881 6l6 425 and look new. The owner told me the unit was recently retubed. Eleven of the power tubes are color marked with a brown dab of paint near the bottom of the tube socket. One power tube is color marked with a green dab of paint at the base. Questions: What gives with the green marked tube? Also, how do I know which tubes are matched? The previous owner did not mark them when he packed them in foam. If I plug the power tubes in, will they function normally if I don't have the matched tubes in the right order? Thanks for your help.