With all of this concern about the British 3.7 inch mountain howitzer ("Ordnance QF, 3.7in Mountain Howitzer Mk I, on Carriage, QF Mountain Howitzer Mk 1"), I was going to ask how many of these guns were manufactured and for how long. Hogg says that 70 had been delivered by the end of WWI.
But Wikipedia is sometimes a marvelous source:
On which is a link to an official manual for the piece available online
And a fact sheet of some sort
It appears that production continued on into WWI in India
Hogg gives the models and carriages as follows
"Mk I: Two varieties of this existed; the first half-dozen or so guns had increasing twist rifling, but this was changed to uniform twist and the chamber was slightly enlarged without change of Mark number
"Mk I/1: Introduced in 1944, had a simplified breach mechanism.
"Mk I/2: Introduced 1945, had new firing pin unit.
"Mk I/3: This was declared obsolete in 1960, but no record of its introduction has been found and we are unable to say what the differences were.
"Mk 1: Split trail, wooden wheels, shield, Pack carriage.
"Mk 2: As for Mk 1, but with additional fittings for animal draught.
"Mk 3: Fixed instead of movable spades, otherwise as for Mk 2.
"Mk 4P: Pneumatic tyres, no shield, not capable of being dismantled into pack loads
"Mk 5: Lightened model for airborne troops."
So while the Australians and New Zealand troops might have old worn out howitzers, it would appear that new wartime produced guns might have been used or were at least available?
"(I have omitted n.A.—neuer Artillerie—from the designations, because such use for WWII guns differs among various sources)."
n.A. is 'neuer Art" - new model or mark