That would be news to me. I do not shoot much jacketed nor hard lead but not for that reason. Bullet jackets and lead, no matter how hard, is still softer than steel. I don’t use them because it is easier to develop an accurate, non leading load with soft lead bullets. The only exception is my 1917s. The rifling in those barrels requires jacketed bullets or lead bullets cast from a harder alloy, I use 16/1, lead/tin.
The concerns are several. The metallurgy of the day, certainly, its the dawn of smokeless. The fact that cylinders were not hardened until the Model of 1917. The age of the guns. The value of the guns. Experience over time. Webleys converted from .455 to .45 ACP have been known to blow. I have not seen examples of this with .455 No.2 revolvers converted to .45 ACP which shoots a jacketed but undersized bullet. I bet you will do okay. Having said that I shoot fairly conservatively in my 100+ year old revolvers.