Question on bench bleeding master cylinder

[NovaJ]

I am going to be swapping to front disc brakes in the next day or two, and was wondering if when I bench bleed the new master cylinder, do I need to separate it from the vacuum booster? They were shipped to me already put together, and I didn't know if it would be ok to work the piston with the rod coming from the back of the booster, or if it was a better idea to take it apart.

Any help is appreciated. Thanks.