Hi Bill. Welcome to the forum! You should contact Tom Heller, aka Luger Doc, at:
hellerarms@webtv.net. He may have a strawed Commercial/Navy take-down lever in stock.
I'd like to add your 1917 Navy to the Navy List, but need the full serial number. If you email me at:
normrab@comcast.net, I'll send you a link to the list.
Regards, Norm