The Italian Army used large numbers of the M14 howitzer. They liked it so much it went through two upgrades after
WW2 and didn't finally leave service until 1975. The later ones used the gun shields and the circular traverse frame of the British 25 Pounder.
There very few guns which remained in service that long.
I like your models. Could I make a small point. Artillery pieces are like precision machines - they have to be to withstand the enormous pressures
and forces of firing a gun. Usually artillery pieces are cleaned religiously by their crews so the guns don't show much wear - a bit of dirt or mud on the
gun carriage but the breech and receiver are always kept clean and often polished.