That's a much more impressive achivement considering our host's dad didn't have the instructions. In this Anon's case, my dad had the plans and even then it was no joke.
Here are the original instructions, in case anyone's curious.
https://i.ebayimg.com/images/g/6d4AAOSwfphaUW6u/s-l1600.jpg
https://i.ebayimg.com/images/g/-NkAAOSwcSxaUW6x/s-l1600.jpg

My dad didn't use a rubber-band, either. We visited a fabric shoppe and bought a package of stretch-fabric ribbon which is designed to last for the life of the garment. He improved on the basic rubber-band connection and used two separate hand-tied "stretch-fabric rubber bands". Final assembly involved several custom-built wire hooks (from a clothes-hanger stock) and a great deal of cursing.

To my dad's credit, C-3PO never broke no matter how much I posed him, My protocol droid was tight and frisky when I traded him to a classmate for his (dad's) mint copy of the November 1985 issue of National Geographic which had an incredible skull hologram on the cover.

https://i.imgur.com/lYC4JgV.jpg
https://i.imgur.com/Vy8dHc2.jpg

From 1977-78 to 1985, we're talking about eight years (and counting) of regular play *cough* "posing" of the model. No rubber band could have ever lasted that long.

A great big, big thank you to our host for these spectacular catalog scans!