Theory about Percy

Ok so we know Percy, the hodgepodge of parts that makes a saddle tank with no definitive basis. And some of you are thinking “Why doesn’t he ever tell us what his origins are?” Well here’s my explanation as to why Percy never tells us: He simply wasn’t alive yet. My theory is that Percy was faceless throughout most of his life pre Sodor, and it wasn’t until the final workshop he was at where he got his final modifications was when he became sentient.