Here is the page your serial number is on:
http://www.singerco.com/uploads/asse...NGER_V_nos.pdf
And here is the information
Numbers model numbe made Date
V- 413640 663639 28K 250000 January-June 1908
V denotes where it was made and yours was made in Clydebank, Scotland
What a great find! and yes it is worth every penny....