[Seaplanes]

I have now checked through the files of NARA T-177 roll no. 16 containing among other things, the very important RLM Flugzeugentwicklungsprogramm (aircraft development programs) from 1935 to 1937. Here all prototypes and 0-Serie aircraft are listed, many with W.Nos.
For 01.10.1936 the following info is given for the Hs 123:
Hs 123V-1 W.Nr. 265 1 x BMW 132. First flight in April 1935.
Hs 123V-2 W.Nr. 266 1 x Cyclone. First flight in May 1935.
Hs 123V-3 W.Nr. 267 1 x BMW 132. First flight in May 1935.
Hs 132V-4 W.Nr. 670 1 x BMW 132. First flight in April 1936. Prototype
for Hs 123A-0 series.
Hs 123V-5 W.Nr. 796. 1 x BMW 132J.
Hs 123V-6 W.Nr. 797 1 x BMW 132J.
Hs 123A-0 W.Nr. 628-634 and 788-785. Total 16 aircraft.

In the program dated 01.04.1937, the first three prototypes are no longer listed.
Hs 123V-4 W.Nr. 670 1 x BMW 132A.
Hs 123V-5 W.Nr. 796 1 x BMW 132G. First flight in March 1937.
Hs 123V-6 W.Nr. 797 1 x BMW 132K. First flight expected in May 1937.
Hs 123V-7 W.Nr. not given. 1 x BMW 132K. First flight expected in July 1937 but later delayed until December 1937.
Hs 123V-8 was a conversion of the Hs 123V-2.
Hs 123A-0. Same as above.

Unfortunately, I have no confirmed info as to which factory delivered the various series. Based on the A-0 series W.Nos. and the prototypes W.Nos., I believe that everything from 265 to 976 are from Henschel and the four digit in the 2000 series are from Ago production. But this is guessimations only. Can someone confirm. In case give your source for that information.