Remember you get what you pay for. If you are getting it cheap enough from an overseas dealer you are probably getting a whole bunch of hitch hikers too. I'm sure you get some good ones but I am also sure you'll get a few bad ones too!
I have gotten plenty of good and bad hitchhikers from local rock too. I am getting a great price on this especially the zoo rocks for 2foot rocks covered all in zoos I am still paying less with shipping than I'd spend on rock at the LFS for plain rock not to mention some of these rocks have over a thousand zoos on the rock!!
I am trying to understand how you plan on curing. You are moving all of your reef into a bigger tank minus a few pieces of live rock then are going to put this new rock into the old tank? I think as long as you aclimate the rocks with the corals on them properly you should have no problem with the zoo's (I would drip acclimate them) However, I also think you are going to have a whole lot of die off with the shipping, because of the time it will spend out of the water.
None of the zoos I have ever gotten have been shipped with water and all do fine. The actual ship time is about 14 hours so not too bad. I am taking all the stuff out of my main tank as a precaution for any cycles that happen and also to protect all my zoos and etc from hitchhikers. They treat for nudis etc but that is never a guarantee. Pain to move it all but safer. Plus I plan to sell the 180 when all of this is over with. I am just going to take the plain rock and put it in the 375 and let it run its course. I don't care about a cycle in the tank since it will be a new set up. I was mainly concerned about the zoos to make the least amount of a cycle as to keep them alive. Eventually the entire bottom amount of rock in my 375 will be a bed of zoos. I will post pics as it progresses.