It's supposed to work. But the most important thing is the size of transaction, it's a downside of Zerocoin.

Zerocoin's transaction is about 25-30kb for each because it use heavy math and cryptography.

That's why Zerocoin's dev is now developing Zerocash with reduced transaction size to 288 bytes (downed 98%). We still don't know how Zerocash can achieve this, we have to wait to see Zerocash white paper which will be publish on May 18th.

If Libertycoin is going to adopt Zerocoin's old library, its blockchain size would be huge because there is no way to reduce that 25kb transaction size (unless this is Zerocash).