Hi Jack,
I do have a William as a brother to my Edwin L. Vaughan, though I don't have a birth year for him. The family group sheet I've put together shows at least 13 children, William R. as the first born of the family, and born before 1820. I haven't been able to find anything else putting him at being born in 1803.
Contact me at my email address and I can send you the scan of my family group sheet.
Best regards,
Lori