The one that came on mine was a POS too. The headlight was like a Bic lighter on it's last leg.
Funny.
I think that I might have one of those headlights kicking around in my garage but from memory they could also be sourced from some Fiat but I might be wrong on that source. Trying to source the headlight mounts is probably difficult but I'd try to find someone who has the parts from an SP. Probably the hardest part to find in descent shape is the rubber cover for the clocks that says LeMans.
"I bought mine last year and have not had time to enjoy it like I want to, but was very happy to get it for $2900."
I paid $2,500 for mine and it was running but running poorly. I remember having a hell of a time trying to get it timed with the stamped timing marks until I had a conversation with Dave Richardson who informed me that those marks are probably just a suggestion and I should time by ear and performance. Solved that problem and I proceeded to invest thousands of dollars in that bike.