What a wonderful story. Lucky you.
I have a White treadle but no manual, etc so I sent an email to Huskavar (spelling wrong, but hopefully which machine company). Anyway, I told them it's a White, in cabinet with White done in twigs & gave the serial number.
They replied the next day and my little beauty was made in 1918. If you want to get a date for your new baby you might try that.