No, you cannot on a true basis. The 6 digit numbers tell you "Not long," but other than that it is up for grabs.
Years ago the first 100 numbers were reserved for life members, and 101 to 1000 was for Leaders.
In 1955 I had a 5 digit number from square one, In 1963 I became a Contest Director and a Leader. I had the option for a 3 digit #, which I took.
In the past 5 years, several fellow Club Members have obtained CD licenses and have been allowed to convert 6 numbers to 4 digit numbers.

Some have dropped out for several years and received their old numbers back while others have just been loaded down with the 6 digit numbers.
Im sure there is a plan, however you cannot really tag a date to a number.