I think that in fact you might be mistaken.
650 is quite a bit lower than my chassis number and my car was built middle of last year. That's before even considering AeroMax.
Can we bring this
list of Aero chassis numbers up to date with the newest models purchased. As Shooter has said, I don't believe the 500-series of chassis numbers was used, and we certainly don't have a 5-series chassis on the TM list.