The Nafziger OOB for Trento on Aug 22nd 1942 on pg.166 of the book lists two battalions attached, quote: (my italics)
254th Artillery Battalion (attached from XXI Corps, sometimes identified as the 354th Artillery Battalion (1st, 2nd, 3rd batteries each 4x 77/28)
355th Artillery Battalion (attached from XXI Corps, sometimes identified as the 357th Artillery Battalion:
1st, 2nd, 3rd Batteries each 4x 77/28
412th and 414th Motorised Anti-aircraft Artillery Batteries each with two 20mm AA guns
In typical Nafziger misprinting fashion, the latter two may be indented incorrectly, as it looks as if the two 20mm Batteries are part of the 355th Battalion, and not the parent 46th Artillery Regiment. Incidentally, both battalions are indented to appear as if they are part of 46th Artillery Regiment, indicating they were attached to the 46th Artillery Regiment.
Also in typical Nafziger reportage, the 4th Anti-tank Battalion held at divisional level of Trento is listed as having the 51st Semi-motorised Medical Company and 51st Motoriesd Administrative Company under command, the way the text is indented, but with no anti-tank guns listed.
Also in typical Nafziger fashion the two artillery battalions with 77/28 are then repeated on the same page further down as corps assets of the XXI Corps, but with no page break to show corps assets as separate from Trento. On first reading they have made it to look like the 7th Bersagleiri Regiment, 8th Artillery Regiment (152/37, 149/28 and 149/40), 27th Motorised Engineer Mechanic Battalion, 65th Motorised Engineer Communications Battalion and a Supply Battalion are all part of Trento Division! Regular users of Nafziger sources will be used to this.
The book is on Ebay at £12.11, from books--etc, it's probably worth that just for these OOBs,
Mark