Albert LeCoultre (somewhat related to myth-bloated Blancpain ? Need advice here, thanks), presumably not related horology-wise to Antoine LeCoultre, which usually is associated with low-grade movements, mostly cylinder escapement junks
I've also got a Bigelow VC with the 1884 Patent regulator + Guillaume Balance (traits qualifying for VC Observatory grade ?)
It came from the "evil bay" costing me about 400 bucks 3 years back, did I get a good deal (of course at that price level it is re-cased in a mediocre nickle case) ?
One more thing, Ed Koehn signed its "Tiffany"s in cursive form, both on the dial and movement. So even if it is replaced with a PP Tiffany dial, the incongruity of signature with that on the movement will definitely downgrade your "very important" Tiffany
Sorry, this definitely is a Jules Monard of Geneva who produced so many PL high-end watches for the U.S. jewelers but overwhelmingly most were signed only with the jeweler's name.
Here is a rare one (#23248) co-signed Hamann & Koch NY: