Ya, that particular terminology can get a bit confusing. And to make things worse, some sources utilize different nomenclature altogether.
I might be mistaken but I believe I've seen the swivel type and rigid type with either/both O-ring types. In other words, being rigid or swivel does not necessarily affect the O-ring location. That makes even more variables (if I'm right about it, been awhile since I looked at this stuff).
Another area of confusion with AC parts is the barrier hose sizes. Typically the fittings go by -AN sizes, with standard sizes of hose that match. However the actual size of the hose is not the same as the AN name indicates. For example a -8 AN is a 1/2" fitting, but the matching barrier hose isn't 1/2". Although the hose is often referred to as 1/2" hose. Then there is the thin wall barrier hose. It has different dimensions and uses different fittings. But the fittings are still referred to by the same -AN sizes.
Although the hose and fitting sizes tend to be somewhat standardized for their application (i.e. the sizes used for the high pressure side vs the low pressure side, etc), that isn't always the case.
You really have to watch carefully what you order when buying this stuff online. This is one reason I planned to scrap all of the old system and make new lines throughout. Still haven't decided if I want to reuse the hardline portion. I'll have to look into their fitting sizes more first.
You can buy new "bare" rigid line in basic lengths and weld on new fittings to suit your needs. But I'm not confident enough with my welding skills to do that.
Like Larry said, plumbers have it even worse.