Well, it depends on how the armour is labeled. I'm not sure by what you have said as to how its labeled. During the time you could first make the dragon armoue it had a differant label then the ones you can make now. I foregot atm the exact way it reads, I would have to go and compare my armour sets and see. But the earlier armour with a differant name is collectable, especially to those collectors who exhibit varities of armour in thier museums. I have one breast plate, I think its red that is dragon armour but is missing any mention of it being dragon armour. Its the only piece that I have found like it, its not to say thier are more of them, but its interesting. Pricing is very subjective and you just need to maybe post pics of what you have with the text associated with each piece, that way a player could help you better on these boards.
The OP is talking about "sea serpent ___" and "dragon scale ___" items which are no longer makeable with that tag. Now they say "blue dragon gloves" etc.