I've seen s/n from the 15,000 range up into the 30s 32,000 ... have you ever seen a six digit s/n? 207,nnn?
I recommend doing a Private Message if you want to talk to him. Most people who read this will have no clue what you are talking about. Just click on his profile photo and then click "Start a Conversation"
Yes, but I can be slow to answer PMs sometimes. To answer the question yes ACG reached the 6 digit serial number level with the ACG 14 variety around 1997. Everything after that has 6 digit numbers The highest number shown in the slab book was on an ACG 26 variety SN# ACG302239