Peter,
Most "main" products are given sequencial serial numbers as they are made, regardless of model and type, which is unusual, but it does mean that there is a broad correlation, in as much as the serial numbers have risen steadily over the years and most dealers will (or should !! ) know roughly how old a product is at a glance.
There are a few exceptions to this rule ( Bsnd 2, Blink active, Beoport, Serene etc ) but it applies to the vast majority of products.
This serial number passed 20000000 recently, so anything 199XXXXX orlower will be pre 2007.......probably.
FAQ ?? - it would be an honour.
Bang & Olufsen of King Street - Manchester,UK. SKYPE - beokingstreet