Richard,
My understanding of Hurlow serial numbers is that the second and third digi ts indicate the build year. For example, my 1972 chrome-plated W.B. Hurl ow has serial #172102 on underside of bottom bracket and on fork steerer tu be.
Photos of this complete bike and bare frameset can be viewed at the followi ng Wool Jersey address links:
http://www.wooljersey.com/
You can also read some information about Bill Hurlow at the great UK "Class ic Lightweights" site at the following address:
http://www.classiclightweights.co.uk/
As a reminder, Dale requests proper name/location sign-off on all posts.
Hope this helps!
Kevin Kruger - Grantville, PA