I just got back from 4-day
DCL, with DD3. I used both of or original BC's (I ordered a copy of mine as I could not find the one at home)
Now I will say this...THIS IS NOT A RULE, BUT MY EXPERIENCE....
When we got to the port, the line to check in was long (printer had gone down, so everything was moving slow)
anyway when we finally got to the counter, the CM asked for the documents you needed to have signed and then he asked for BC's I handed them both to him in my handy dandy "important cruise paper folder". Now here is the funny part, both of the BC's were in the plastic sheet protectors, my DD BC is half the size of mine (IDK why maybe because we were born in 2diff states) anyway, her BC was in front of mine so you could only see the top half of mine. Well the Cast member took the handy dandy folder and just looked at the names on both BC's, he didn't want me to take them out of the sheet protectors, now mind you in order to see or feel the raised seal on both of them they needed to be removed from the sheet protectors. Anyway, i thought this was odd.
But remembered this I am sure is an exception and not the rule
So as of to day you can use your BC as long as it is original with a raised seal. Enjoy and have fun.