SPECULATION Why doesn't Owen recognize C-3PO on Tatooine?

Great point! Additionally, I doubt that Owen really remembers a generic looking droid that he barely knew from his childhood.

 

Owen does not recognise C3P0 for a number of reasons. I was reading one official novelisation the other day and it explained it very well.

- C3P0 didn't have gold platings when he left Owen in AOTC and most protocol droids look very much alike. Owen was never very curious in the first place, and thought he had just stumbled upon a random protocol droid.

- It was over 19 years ago when Threepio left the Lars homestead so perhaps Owen had forgotten, or just put it out of his mind.

- As far as we know, Owen didn't find out C3P0's name before he was killed so therefore he had no reason to suspect that he owned the same protocol droid he had owned over 19 years ago.

And Obi Wan did recognise R2D2. However what he said was true, Obi Wan never actually owned R2, and he was mostly used by Anakin. Perhaps Obi Wan didn't feel it was important to suggest that he once knew both Threepio and R2, and it would make no difference to Luke otherwise.

 

Someone else finally realized this! This makes me so happy!