My personal direct experience with firearms only goes back to the mid-1960′s, but my admittedly hazy memory of this type of carry was that it was for DA revolvers, SA revolvers with an empty chamber under the hammer or small semi-auto pistols carried Condition 3. Which was all a part of the concealed carry concept of a century-or-so ago; a concealed weapon was implicitly assumed to be intended as a surreptitious option for personal defense. No “fast draw” capability was expected, or even considered desirable as a safety measure. If the situation warrented a more pro-active weapons stance, you readied your gun for that circumstance beforehand or cussed yourself for not paying closer attention to your surroundings.
I haven’t made any sort of historical research effort on this, but this is my memory of what the “old timers” (my grandfather and his age cohort) said when I first started getting seriously interested in guns back when. I personally have occasionally worn my S&W 431PD in a belly holster at 11 o’clock for a r/h draw, but I’m a few kilo’s away from that option being what anyone other than the Texas legislature would call “concealed” today.As Uncle and several other of his commenters point out, modern holster and firearms designs expand the possibilities of safe carry well beyond those of a more historical standard. Also, modern personal training opportunities and standards alter what was historically considered acceptable (the 4 Rules are important, but were never really more than a recommendation) (let's see who is humor deficient).
Personally, appendix carry (inside the waistband, immediately to the right of center-torso) never has been all that comfortable for me, especially when sitting down or bending and twisting at the hips (as you do when lifting items into or out of a vehicle, for instance). I own shoulder holsters, several IWB and OWB holsters, a belly band holster, pistol pocket guard and even a FAG bag (for when I need to legally conceal a gun but want to create a good bit of uncertainty amongst others as to whether or not I'm actually carrying). Find the option that suits you best and carry your gun in the most situationally suitable condition you hope not to have to use it in.