I think it just depends on the gun, some will stand it and some won't. I shot steel through an ancient 97 Winchester pump for quite awhile and never hurt it a bit. But a friend badly scored an early Stevens Arms and Tool Co. pumpgun that he used on ducks after a couple seasons of it.
I'd say that A-5 must have been scored up a long time ago with the early steel shells and somebody is just getting around to polishing it out. With the new heavy shot cups they put in the shells now it's not so much barrel scratching as it is choke damage that would be the worry these days.