Well, I can't imagine 5.5 not having those folders, since they existed all the way back to at least vers. 3.x. In any case, though, you *could* always drop it directly into the versions plugins folder... Although how that shows on a mac I have no idea. If your copy is inside an app folder, you may have to change permissions to access it, although I really doubt this avenue is necessary, I believe the default locations indicated in the above 2 pics should suffice.
I also may not have been clear enough in my original post that the place you choose for the plugins or extensions is the folder 1 level up from where your plugins folder actually sits, which is why that lesson seemed misleading to me.
So, for example, by default you might have in the files and memory section something like -
[ /home/bogs/Documents/My Revolution enterprise ]
Inside that folder is one marked 'Extensions'. you could probably drop it right in there.
I don't do much with mobile, so I mostly use Mc for my coding, sometimes venturing up to Lc 2.2.1 or even as high as 6.5 (almost never past that), so I don't think I'd be saying it since you already have one of the silk purses in my opinionI might be trying to make a silk purse out of a sow's ear by continuing to use 5.5 (which is a commercial version from before they had an "indy" version). I can compile Mac apps with ease, but anything that requires XCode like IOS apps won't work at all. The versions of XCode required won't install on Sierra.
No problems, just hope the responses are helpful as I had similar issues groking this part of Lc myself.Thank you for taking the trouble to respond.