Is it truth or is it crap?

[Jack]

It's crap.
Or, more accurately, it's backwards.
As others have pointed out, getting a .452 projectile down a .410 barrel has some severe hazards.
Now, folks have shot 410 shotshells in some 45 caliber firearms, like the old Trapdoor Springfield 45-70. Thompson Center once made one of their single shot handguns in 45/410. That was a 45 bore, set up so it could also shoot 410 shotshells.
Taurus currently makes a 45 revolver called the Judge, that is designed to be able to shoot 410 shotshells as well as 45 Colt cartridges.
But, again, note: that's putting a 410 diameter shot charge down a .452 bore, NOT the other way around.