There are a ton of flat hoods out there. Check craigslist and eBay like you have been. Hardest part is probably getting the sellers to look for the date, but I would guess most flat hoods out there are original. My car is a 08C (late 69) and has the original hood with a 26, which would be late June. So I would say from a couple weeks to month before 01B, so anywhere around 49 (1st week of december 68) would seem plausible. My question would be is the hood stamp different for late 67 or 68?