blue steel,
I had asked this same question about a week ago. I was getting ready to fragg my shrooms. and the answer I got was no. I used a total of four shrooms and three pieces of base rock. It has been about a week and some of the fraggs are already opening up and attaching to the rock. and the ones from the original colony already are groing there mouths back. I was quite scared being my first time fragging. But the surgery was a sucess so far. people said they were slimy but I didn't realize how slimy its kind of hard to grip them. Make sure you rinse them in clean saltwater before you put em back in the tank.
good luck.
Right before I fragged my shrooms I came across a thread here by kip "fragging mushrooms" it helped me alot. You might want to do a search and take a look at it.