I'm not convinced that it's early 1970s and heavily frankenbiked. I don't know many owners who convert from wired-on to tubulars. It could be a C-34, which had a tubular option. While, it does have stamped dropouts, I'm used to seeing top tube cable stops on the boom era, entry level models. The presence of cable clips could indicate something slightly level and later, which would be consistent with the drivetrain. The post also looks to fairly large diameter. This may be some sort of tretubi. @
bertinjim may have some more insight. If the price and driving distance was reasonable, I'd probably go have a look.