How can I determine the size of a homemade gown? Sewing Machines Parts and Sales in Los Angeles

I have a beautiful wedding gown and veil from the 1920s (I’m guessing from the style). I don’t know its history. There’s no tag of any kind, it looks custom or homemade (sewn well, just not commercially manufactured). I’d like to sell it. Is there any way to determine the size from the measurements of individual parts like the sleeve length, shoulder to shoulder, neck to waist, arm hole, etc.?