I get all my retrospiralis from Everglades Nursery (aquaticplantdepot.com), which is a very reputable aquatic nursery that has been around for a VERY long time. In fact, if I understand their history correctly, the owner was somehow instrumental in convincing the eventual owner of Florida Aquatic Nurseries to go on and get that business started. And we all know, now, that FAN is probably the largest aquatic plant nursery in North America. Chances are, anyone who buys plants from an LFS in the United States is probably getting FAN plants. I've seen their retrospiralis at a LFS, and it looked exactly like what I get from Everglades.
Anyway, the folks at Everglades are very knowledgeable, and have been doing this for generations, so I trust them. That is why, even though I've never flowered a specimen before, I really believe that what I think is retrospiralis IS IN FACT retrospiralis. That being said, I still believe that the OP has retrospiralis, or at least it looks like it.
I've never had spiralis before, so I can't comment on it, but many people here do, and according to their photos the leaves are wider, and it doesn't grow as tall. Also, the leaves are more (I don't know what adjective to use here since I'm not a botanist!) "wavy" or almost "crinkley," whereas the retrospiralis is almost a smooth, flat, and thin leaf.
My retrospiralis has never gone to any other color but green (with a few reddish colored specks, or dots), so I want to say that it doesn't get the red color that balansae gets. And while we're on that subject, since balansae is not a species name, and is actually C. crispatula 'balansae' it wouldn't take a stretch of the imagination to see other versions of crispatula do the coloration thing, so maybe if a plant that was thought to be retrospiralis goes very red-colored, it might be another variety of crispatula.
Wow that was a long post.
This is all anecdotal information not based on any kind of an "official" knowledge of botany. Just comes from my own experience, and my disclaimer is, some or all of it could possibly be wrong.