Bösendorfer serial number location

[jazzertim]

Pardon my ignorance, but...
where is the serial number located on Bösendorfers? I looked on the soundboard under the music desk, and looked around the "signature", but didn't see anything. I'm guessing the piano is circa 1970. Also, is there a free online "bluebook" type of service to get ballpark prices for used pianos?

[G.Fiore]

 J, the serial # can be found a little right of center on the plate, in front of the tuning pins.  They also sometimes placed it on the underside of the sound board, usually near the center. If from the 70's there should be no less then five digits in the serial number.

[jon-nyc]

By the way, on a Bösendorfer its called an Opus number. 

[Brian Lawson, RPT]

By the way, on a Bösendorfer its called an Opus number.

May woord, How Posh !