You did say munich 3, and the only munich 3 is the cara, so a fair guess by GB.
Anywho, I'd be tempted to go more
60% pils
25% munich II
13% vienna
2% carafa special III for colour
Hops should be good.
As there is pils in there I would be doing a 90 min boil, and depending on yeast a diacetyl...