I was given an Attack-4 radio that is in great shape and works perfectly, after putting a new battery pack in the TX. Is there any way to tell when it was made by the serial number ?. I do know it was at least as early as, or prior to March of 1992, because that is the date on the RF check sticker. The battery pack alone cost as much as the whole radio is worth, I realize that, but I was just wondering what the date of manufacture was, for curiosity's sake.