I looked through files and I think it's better to leave the patch as it is.
The difference between build 15 and 16 lies in video.vid archive. Including this change in patch would increase its size up to 600 mb. So it's better to download new build anyway.
Unfortunately, the presence of Armorer bug in Heroes Chronicles needs further research.
I'll try to hunt it down in my free time, but can't give any ETA.
I have downloaded the HOMM3 installer from my library but I do not see any other updates. Is the Installer (v. 4.0) all I need to play the game and the updates included in it? thanks