I do not think I have the company documents to explain the Curtiss H87 designations. As far as the Air Forces are concerned they are P-40E and E-1. The USAAF lists the British order for Tomahawks as HK-81A, for Kittyhawk I as HK-87A.
What the table in message 24 calls delivery dates are acceptance dates or else aircraft were being accepted and delivered on the same day. Also should H87-B2 be H87B-2? 40-358 accepted 20 August 1941, 40-382 to 681 accepted 24 June to 16 October 1941.
The H-87B-2 are all from contract AC-12414 dated 26 April 1939, 524 aircraft built as 199 P-40, 22 P-40D, 301 P-40E, 1 XP-40F, 1 P-40G
The H87-A2 are from contract AC-15802 dated 13 September 1940 or its' supplement 1 dated 6 October 1943 (so well after all the P-40 on it had been built), 1,842 aircraft, 131 P-40B, 193 P-40C, 519 P-40E, 699 P-40F, 123 P-40F-5, 177 P-40F-10
The H87A-3 are from the first batch of 420 USAAF serials from Contract DA-3 dated 12 May 1941 for 1,500 P-40E-1, the H87A-3 from the second batch of 1,080 USAAF serials. The RAF essentially had one block of serials, ET100 to EV699, (no EU serials issued, nor EV000 to 099)
At the moment the Curtiss designations mostly track the USAAF serial allocations, acting like North American Charge Numbers.
In production order
P-40 from AC-12414 (May to October 1940)
P-40B from AC-15802 (February and March 1941, plus 1 more each in April and May)
P-40C from AC-15802 (March to May 1941)
P-40D from AC-12414 (May and June 1941)
P-40E from AC-12414 then AC-15802 (June 1941 onwards)
As delivered in the US P-40E AC-12414, 280 US, 21 USSR, AC-15802 409 US, 110 USSR.
Contract DA-3 P-40E-1 315 US, 444 British Empire, 708 USSR, 6 Brazil, 27 China
As is known in Australia the RAAF and USAAF ended up flying a mixture of E and E-1 from US, British (Australian) and Netherlands orders. Similar for the Red Air Force