The original pilot for Happy Days was a segment on Love American Style starring Ron Howard, Marion Ross, Anson Williams, and Harold Gould. It was called Love & the Happy Days

www.youtube.com/watch?v=51-sUjzbk18

Youtube says that video is not available.

Sorry, the link doesn't work, but you can get it if you type in Love and the Happy Days on Youtube.

I found the first part of the original pilot (which lasted around 9 or 10 minutes) but the other parts of the episode weren't there.

I continued to watch the pilot of Happy Days and did anybody notice that it was called Arthur's and NOT Arnold's in the pilot? How long did that go on for?

I continued to watch the pilot of Happy Days and did anybody notice that it was called Arthur's and NOT Arnold's in the pilot? How long did that go on for?
Only that episode.

The first episode of season 1 has it called Arthurs

the pilot was also on hulu.com; I don't know if they still have it. They did a couple years ago when someone on here posted the link to it.

However, there is a blooper in one of the early episodes after the name changed to Arnold's where (I think it was Potsie) someone said, "I have to go talk to Arthur."