This bust appears to have been made for the sequence in A Clockwork Orange when the Droogs break in to the house of Catlady [Miriam Karlin]. Catlady subsequently picks up a bust from the desk and uses it in her attempts to defend herself against Alex [Malcolm McDowell], shortly before he kills her.
The vendor worked for Stanley Kubrick on A Clockwork Orange. On one occasion he noticed this bust on Kubrick's desk and mentioned to the director that Beethoven was his favourite composer. Kubrick apparently responded by giving this bust to the vendor as a memento.