You do know, of course, it doesn't even matter at all what the law says, right? Police can - and will if they choose - do just about what ever they like and let things settle out later. Law? Nah, not much. At the moment, primary concern of the officer is not your civil rights. Quality of the wording in any law is irrelevant. A cop who is about to make your life heck over a clamshell holster is already going to make your life heck, regardless of the holster. That is the real problem.
So, the first holster is obviously a holster. Open carry. The second is not. Concealed carry. Otherwise, ALL fanny packs, purses, pockets, can be called open carry.
If you are worried about a clamshell, my advice, worth the price it is billed, is to not use one when you open carry. If things have gotten to the point that you are arguing technicalities over holster design never used for concealing a firearm (previous use does come up here), then they have only begun tacking on extra counts to what ever charge has gotten you into trouble in the first place.