The 3rd Armored Cavalry Regiment does not contain any "battalions" (did not contain in 2003, now their makeup is different). Because of historical and traditional reasons, United States Cavalry organizations are designated as squadrons (but are battalion-sized units) within the regiment.
Back then, an ACR (Armored) comprised of three ACS (Armored Cavalry Squadrons or ground squadrons), a Regimental Aviation Squadron and a Regimental Support Squadron. Tanks are only located in the three ground squadrons.
The ground squadrons contained three Cavalry Troops (company sized units), a Headquarters Troop (HHT), a tank company (the tank unit is always called a company) and an artillery battery (a traditional name for a company-sized artillery unit). Additionally, the Cavalry troops had two Cavalry platoons and two tank platoons (usually the second and fourth platoons, with 1st and 3rd platoons being the Bradley platoons).
Because it is organized as a regiment, the company/troop lettering is sequential. First Squadron contains A Troop, B Troop, C Troop and D Company (tank); 2nd Squadron contains E Troop, F Troop, G Troop and H Company (tank); 3rd Squadron contains I Troop, K Troop, L Troop and M Company (tank).
There is never a J company or troop because long ago a script letter "I" could be confused with a "J", so they skipped over J.
Bottom line, the markings are correct, but Tamiya's identification should replace the word battalion with squadron. Based on the organization I listed, you should be able to extrapolate just about any tank bumper number in the regiment.
As to the word in the center of the tank on decal #17, it looks to be a tank name.