Randy is correct....Darren's is a '76.....nice bike! There were 2 generations of '75 frames. The way I understand it they all had the flared seat stay lug. But the earliest frames had a tapered coaster brake bracket like my short frame '75....
Mine is the only one I've seen except for waza007's.
What is your serial number waza? I think they are in the early to mid 11,000 range.
I know of a high 11,000 number frame with the later hourglass shaped coaster bracket that was carried over to the 76's.