The extra lever above the presser foot lever is used when sewing thick fabric sandwiches:quilts , woolens, etc. There are some important things to know about removing the faceplate... Don't do it until you've read the manual/seen the you tube videos.
I believe Davis hand cranks are very rare. Davis also made and badged the VF for other sellers, so finding a cabinet/irons wont be difficult. One of the Minnesota models, H?, and a few others. There is a Davis VF group on Facebook.