I'm trying to find the manufacturing date of my Neumann U87 P48 serial # 08777. It has a 3pin xlr connector, battery compartment and this mic. still sounds great by the way. I have been told that it is probably from the 70's but would like to know for sure for my own edification. Also, can I still get a replacement grill screen. Also, what would be the current value of this mic if anyone knows. Thanks so much!