Hi there.
The serial number,
9126037, points to the 6037th frame built in 1949 (December). Could have been purchased in 1950 and so fits with your father's date! So... it is indeed a "real Claud". I agree, looks to be the Avant Coureur - either model 1 or 2 according to http://www.nkilgariff.com
catalogue for that year. Those are not lugs, rather this is Claud Butler's bilaminate construction. Looks to me that besides a lot of "kit" upgrade it also has been repainted. The Avant Coureur is advertised as having chrome on fork crown and catalog pics shows chrome on lower front forks as well. Fork crown looks similar to bike in catalogue picture. You might check if indeed chrome under those areas? You have a classy frame and indeed worthy of preserving this piece of history.
Doug
Last edited by allend; 04-15-16 at 06:19 PM.
Reason: added pic