Mike
-You can't have mine.
Have you accessed it yet and have a sense of what it looks like? I've never taken mine down.
Dixie Gun Works used to have an assortment of springs. Sometimes one could be fitted using their stock.
If the Manhattan spring turns out to be the style with the little intregal locking pin, or stay which is at ninety degrees to the spring bow, then its a rougher deal.
Remember once trying to replace a W.C. Scott 10 gauge top lever spring. Got as far as some illustrations from England. One appeared particulaly well suited, but when I ordered I was told it couldn't be exported because of liability concerns. One of our fine members from Pennsylvania saved my neck on this one as he had made two for his 10.
Remember, your Manhattan is very probably an early Sauer made sidelocker. There's a German Double club around somewhere - - I apolgize for not having the name correctly - - who may have someone to steer you right. Hopefully, you'll get good counsel here, bye and bye.
What's your Manhattan's serial # range?