Cresarrow
IWC began supplying movements to Henry Blank/Cresarrow at least in 1916 for wristwatch movements and certainly earlier for pocket watch movements.
I would suggest the IWC did not have the resources at the time to market watches in the United States. Henry Blank with his connections to "high end" jeweller's Raymond Yard; Shreve, Crump and Low; Black, Starr and Frost; Oscar Heyman & Co; Grant A Peacock; Neiman Marcus; and Tiffany & Co though the supply of jewellery was a perfect fit for IWC. Whether Henry Blank approached IWC or IWC approached Henry Blank will probably never be known but it was an arrangement that suited both parties at that time. It was only later when IWC wished to re-establish itself as a brand in the United States that it had to do so from scratch. IWC meant nothing to the buyers of either Cresarrow branded watches or those with IWC movements and Cresarrow cases and the dials marked with some of the jewellers above.
IWC production figures don't give us much of a picture of what uncased movements were sold. What is important is the sales figures, and in particular the break down.
1929 Sales 25,422; Gold 14,414; Silver 6050; Steel 1500; Uncased 3,457
1933 Sales 3,912; Gold 2,453; Silver 520; Steel 661; Uncased 278
1937 Sales 16,151; Gold 4,328; Silver 678; Steel 10,271; Uncased 856
These figures are from Tolke and King page 51 and it's unfortunate that these figures are not available for both earlier and later years to complete the picture. Uncased movements in 1929 accounted for 13.6% of IWC's sales falling to 5.3% in 1937.
I would guess that Henry Blank/Cresarrow were taking the majority of these movements given that IWC watches bearing the distributor's name, eg Stauffer & Co were made in Switzerland.
Prior to the First World War, IWC also supplied Unitas-Praezisionsuhren-Fabrik with a large number of movements.
The argument that IWC supplied movements of a lesser quality to these companies is irrelevant; IWC still made the movement.
While I accept that an "Extract from the Archives" can only reflect a watch that was manufactured and cased by IWC, I believe that IWC should acknowledge the movement they manufactured, and the movement only, contained in watches supplied to those firms that cased them. If IWC has records indicating which firm bought the uncased movement that should also be acknowledged, but with no recognition of the watchcase.
Cheers from the cellar.