A simple answer to your question is yes. Just imagine 48 volts being fed into your mic inputs and then that being amplified by the gain of the mic pre. The 48 volts was never intended to get into the mic pre electronics, thus, the blocking caps. You could retrofit them obviously. And while you are at that, you should also install suppressor diodes to deal with the turn on spike created when PP is first switched on. This stuff should already be included in your PP unit though - no idea why it apparently isn't.