@Georgieboy58
Three years ago I was on a watches exchange event for buying watches.
A man ask me there whether I sell my Sub Sea Pilot (I wear it on this day).
I said no and we started a conversation about the Sub Sea Pilots.
He told me his father was one of the designers of the Sub Sea Pilots.
After a time we came to the limited edition.
He explained that the limited edition have a glas bottom and a different bezel.
I asked what's the different between the normal bezel and the limited bezel.
He said the limited edition was more a pilot watch instead a diver watch.
Due to this the glas bottom (nobody wants a real diver with glas bottom) and a bezel with small teeth for more grip in the cockpit.
I believe him because he was an expert on this watches but i have no confirmation for you