Help with year on my Twinn Sport??

[Shelbygt]

The serial is EP804549 which alludes to it being a late 70’s manufacture. I was thinking Schwinn discontinued this design and went to all step-through front and rear. Maybe because it’s a 10 speed Sport. Can someone help me on this?
I have an affinity for Twinns. This makes number 5 for me. Great time with the wife and such a nice ride with the longer wheelbase.

 

[Shelbygt]

I found the serial on the front fork neck.

 

[GTs58]

Looks like that has an oval head badge. The actual build date should be stamped on the badge, usually next to the letter I. The serial was stamped in May 78 and it's a high number so maybe late May. The four numbers stamped in the head badge is the julian date and the last number is the last number of the year.

 

[Shelbygt]

Thanks brother!