Get rotation or direction from selected object (polyline)

Thanks guys, I learn a lot this week. I was able to apply the rotation from KirkWM suggestion.
I added the Curve.CoordinateSystemAtParamter with the 1 parameter… when I isolate that I do get the blocks inserted at the end point, however I don’t see how to add those points to the existing list of points. I did look at the primer list helps but didn’t see how I could add to the my list given how my script was setup. or how I’d add if I started with a new script. I’m still pretty new at this so some of the terms still are still new. would it be possible to show how to add that additional point a list.

Thank you so much for your help.
runway-lites.dwg (1.4 MB)

INSERT RUNWAY EDGE LIGHTS BY POLYLINE.dyn (79.3 KB)