Possibly a mythologized version of the man who first invented droids.
“Let Us make droids in Our image.”
So, This Guy … created droids. Anthropomorphic and non, and placed them in the dew catcher farm, er… garden, and said unto them: "Be fruitful and multiply high order primes. Act prissy and whiny, and sometimes feisty. And have in subjection all the machines in the farm, er … garden. And This Guy saw it was fairly decent. And it became morning, and it became evening, another day just like all the rest.
Greenberg.
I agree. During the eras when the Jedi are active, “normal people” recognize that they have special powers, but don’t seem to care very much about why they have them.
You mean something like Silicon Heaven?, it must exist, if it didn’t, where would all the calculators go?
Actually, post-prequels, that line has weird connotations of just who he might be thanking. I mean, we know who his maker is now, right?
But he didn’t, not in episode 4. So C3PO could have believed that he was created by whatever he’d been told, like a mythical super-droid who rules silicone heaven, some great engineer, or Dave Cloister.
Hopefully, they were beyond the need for the lies of religion of any kind.
Oh, I know he didn’t know, thanks to the memory wipe, but still, bottom line it, he’s thanking the big bad of the movie. Which is weird.
Well they’re not Southern Baptists. Not with all that dancing 
Maybe Jehovah’s Witnesses — I notice no one seems to have birthday parties.
I may be the only person on the InterWebs who will admit to never having seen the elusive Star Wars Christmas special, but that would seem to imply that there’s some version of Christianity in that area. And I don’t recall hearing anything out of that to imply they’d be Catholic, which would lead me to think they’re likely Protestant.
They drink, so they don’t seem to be Mormon. The use of some surgeries and such would rule out being Christian Scientists?
I don’t remember reading anything in the EU books about them having coffee after service though.
Technically, it was the Star Wars Holiday Special, and the holiday that the characters are celebrating is a distinctly non-denominational “Life Day”.