Hi Jeff,
Thanks.
I have just found "La Guardia alla Frontiera" by Massimo Ascoli on line and this seems to answer my queries.
As one of Maurizio's maps shows above, Monaco did not fall under 4th Army but fell within an area taken over by Italian frontier troops, as you suspected from the photo. In March 1943 both their 1o Settore di Covertura and its Sottosettore 1/a had their command posts in Monaco. In the region Cap Martin-Punta Mala-Mt. Argel the latter had 2o, 3o, 4o and 6o Caposaldi with 1o and 7o Caposaldi in reserve and 5o Caposaldo in Fort Tete de Chien. It is not clear if any of these were actually deployed in Monaco, but they were certainly deployed all round it.
Similarly, XLVIII Gruppo Art G.a.F. had 602o btr. (with 100/17 pieces) positioned at Cap Martin and 403o btr. (with 105/11 pieces) deployed at Cap Ail, on the coast either side of Monaco. It seems clear that there was no Italian artillery in Monaco itself.
I am unclear exactly what a "caposaldo" comprised. In the same book I found three "subsettori" totalling about 1,500 men and another two "subsettori" and an independent "caposaldo" totalling about 500 men. It would appear that the number of men in a "caposaldo" depended on the size of the fortification it garrisoned, which could vary, and the number of "caposaldi" in a "suttosettore" could vary as well. I suppose a "settore" was roughly equivalent to a regiment, a "suttosettore" roughly equivalent to a battalion and a "caposaldo" roughly equivalent to a company. Is that approximately right?
However, as they had been uprooted from their normal fortifications in the Alps, it is possible that the seven "caposaldi" of Sottosettore 1/a no longer had strengths related to fortification size.
Cheers,
Sid