Correct way to fit magazine in a 1911.

I've never done that before ! Slam a mag into the grip, rack it back & go.

Personally I cannot see how this would affect the gun in any way (replica or the RS), to get the slide to lock back requires an empty magazine or fiddling with the slide lock on a replica version. The replica has a nubbin on the magazine that is raised to its upmost position when the magazine is empty which pushes the slide lock up to catch the slide before it goes back into battery.

Seems illogical to me, as it does no harm to the replica gun, serves no actual functional purpose and requires fiddling with the gun prior to loading the magazine into it. The only thing that I can think of is the fact that having the slide locked back shows the gun to be 'safe' prior to loading but that's a different thing entirely.

Whoever told you that needs to be asked the question 'Why ?'

Ive not heard of this on any 1911 , However the browning Hi Power DOES require the slide to be locked open BEFORE removing the mag
the reason for this is because moving the slide back also moves the valve knocker out of the way , 
faliure to lock the slide back on the Hi Power can sometimes cause the valve knocker to snap
The 1911 uses a different system 

i know .... i bought 2 of them direct from taiwan just in case lol