As the Paratroopers of the 506th PIR moved into Le Grand Chemin to their fore in the grounds of Brecourt Manor, was a Battery from the 191st Artillery Regiment, 91st Airlanding Division.
Now I cannot claim to have identified this particular unit from the sources I have personally or at least I cannot verify it was a battery from that Regiment which was positioned there from the secondary sources I own and have used as reference material. But the Skirmish Campaigns-Normandy '44-First Hours in one of the enclosed scenarios identifies it has being from the Second Battalion. Olivier Perrony (Perrys Heroes) in his recent article in Wargames, Soldiers & Strategy No 60 goes as far as to identify it as Battery No.6 of 2nd Battalion, 191st Artillery Regiment.
I would also draw your attention to this excellent site WWII Armed Forces OOB by Dr Leo Niehorster. In particular the following link to the organisation of the 91st Airlanding Division. This Order of Battle states that the 1st & 2nd Battalions of the 191st Gebirgs-Artillerie-Regiment (Mountain Artillery) were equipped with 10.5cm GebH howitzer.
This howitzer could be broken down for transport, on mules if necessary, since it was designed for use by the Mountain (Gebirsjager) Divisions.
Now The Lions of Carentan, FJR6, 1943-1945; GRIESSER,Volker; states that on 6th June 1944, Major Von de Heydte (commander of 6FJR), commandeered the 4th and 8th Batteries of the 191st Artillery Regiment, plus a Battalion from the 1058th Infantry Regiment when he encountered them near to St Come du Mont. Plus GRIESSER states that St Marie du Mont was occupied by a company from the 1058th Inf. Regt. on D-day. All of these units were of course from 91st Airlanding Div..
From this information one can conclude that the units in and around St. Marie du Mont on the morning of 6th June 1944 were most likely to be from regular army formations. Now this is of some importance since there is debate/controversy/opinion, that elements of the 6th Fallschirmjager Regiment were in command/protecting the guns at Brecourt Manor. Yet the 1st Battalion, 6FJR at least does not seem to have begun its move towards St. Marie du Mont from St. Come du Mont until the afternoon of D-day. 2nd Battalion was to move from the same area towards St Mere Eglise and 3rd Battalion remain in the vicinity of Carentan/St. Come du Mont.
Its Stephen Ambrose in his Band of Brothers who makes reference to the guns being manned by Fallschirmjager of the 1/6FJR. Since the assault on the battery took place on the morning of 6th June 1944, this would contradict both Griesser and Steven J. Zaloga (with Ken Ford & Stephen Badsey) (Overlord, The D-Day Landings; Osprey (Compilation from Campaign series)) both of whom state 1/6FJR moved out afternoon/early evening. Is this confusion because Batteries from 191st Art. Regt. where attached to 6FJR and the 91st Div. was designated Airlanding (Luftlande)? Or because German units were dispersed throughout the Contentin Peninsula; were there in fact Fallschirmjager near to or at Brecourt Manor? At present I personally do not believe Ambrose is correct and I'm going to say no to Fallschirmjager at Brecourt.