That piqued my curiosity too. I checked Davidson's Galley of Guns & S&W currently makes two models one in .45LC the other in .45AP
And why would her brother get her a .45 revolver? Like you say that's a 'lot of gun'. Why not a .38 special or 9mm?
Note: I don't know too much about S&W, like the N frame you mention, I'm more of a Colt kind of guy.
I'm fond of the single actions myself, and i definitely have a weakness for old Browning Hi-Powers. Maybe obsession is more like it, i currently have 25.