Robert Y. Hood

I just got my first pair of Cornwalls. The ser# on the speakers are 12R263 & 12R264. They have plywood cabinets, and sound wonderful. I like them better in some ways than my La Scalas. Does anyone know how I can find out when they were made, and perhaps who bought them, etc. They don't have the original tweeters in them, even though they sound great. Should I replace the tweeters? How do I find original tweeters? Thanks in advance!