I tracked down the Operation Olympic TO&E for the 1st Cavalry Division (Special) in Gordon Rottman's Osprey book "World War II US Cavalry Units: Pacific Theater."
Amazon link here:
The 1st Cavalry had two brigades each of two regiments.
Each Regiment had two squadrons (battalion equivalent) that in turns had three troops (company equivalent).
Roughly, the Cavalry lacked between 1/2 and 2/3 of the crew served heavy weapons of an equivalent US Army Infantry unit. This showed up in their manpower numbers at equivalent units of organization.
From Page 13 of Rottman's book:
Squad - 8 men -------- Squad - 12 men
Platoon - 32 ----------- Platoon 41
Troop - 165 ------------ Company - 193
Squadron - 521 -------- Battalion - 894
Regiment - 1726 ------ Regiment 3207
The 1st Cavalry Division started off the war with lighter 75mm
howitzers in two of it's four direct support artillery battalions with
no general support guns. The idea being in 1941-43 that a 75mm and a 105mm battalion supported each brigade.
In 1942 the Reconnaissance squadron was split into an independent light (later medium) tank company (the 603rd independent tank co.) and a mechanized cavalry troop [302nd Reconnaissance Troop (Mech)].
For the Leyte campaign one of the 75mm gun battalions got 105mm guns and in the the Luzon campaign the second 75mm howitzer battalion got 105mm guns. A 155mm howitzer battalion was attached for the Luzon campaign. The sources I have looked at are conflict on if that 155mm Btn became an organic unit for the Operation Olympic.
Pages 14 and 57 of Rottman's book tell the tale regards the 1st
Cavalry Division's Operation Olympic force structure.
Each Cavalry Regiment would get both of it's squadrons rebuilt to the US infantry TO&E with the Squadron Weapon Troop getting turned from an eight heavy machine gun (M1917A1 .30 Cal), machine gun company into an six 105 mm cannon company. These companies would have M7 Priest SPMs.
There would be no regimental anti-tank company like an infantry
regiment and the Cavalry regiment's support units would be 2/3 the size of an infantry regiment, in keeping with one fewer
Going into the invasion beaches of Kyushu, the 1st Cavalry would be short one infantry battalion (8 vs 9), three anti-tank companies (with either 36xM-18 SPM or 27x75mm RR short depending on the Division) and possibly a 155mm (how) Btn compared to a regular line infantry division.
On the other hand, it would have an organic medium tank company (18 M4A3 Sherman), an additional Cannon Company (6 X M7 SPM) and four 105mm artillery battalions rather than the standard infantry division with three.
What Rottman also mentions, and I had not heard before -- was that the 112th Cavalry Regimental Combat team was being reorganized in the same manner as the 1st Cavalry's regiments and was to be attached to the 1st Cavalry, giving the re-enforced 1st Cavalry Division ten squadrons/battalions of cavalry troopers, a medium tank company, 5xCannon Companies, 5x105mm artillery battalions and (possibly) a 155mm artillery battalion.
See also this link
on the 1st Cav's "Sioux Code Talkers --
"During the fall of 1943, more changes came to the Division. On 11 October, the firepower of the Division was improved by the activation of the 271st Field Artillery. In the reorganization of 04 December, weapons troops "D" and "H" were added to each of the regiments. The 7th Reconnaissance Squadron was reorganized into the 603rd Light Tank Company and the 302nd Reconnaissance Troop (Mech). The 302nd had a specific Table of Organization and Equipment (TO&E) which incorporated
a unique radio unit with troops of Lakota and Dakota Indian Tribes who used their ancient tribal Sioux language to communicate with other divisional headquarters troops. This secret organization, formed in the foothills of Australia and later to be known as "The Code Talkers" was recruited at the direction of General MacArthur. The close-knit group of individuals, Phillip Stoney LeBlanc, Edmund St. John, Baptiste Pumkinseed, Eddie Eagle Boy, Guy Rondell, and John Bear King took their task seriously. They saved many American lives using their language as an unbreakable code to fool the Japanese throughout the subsequent Island Campaigns."
This is the link for the attached PNG for the 1st Cavalry's Operation Olympic Force structure --