My initial thoughts were...... yes, you want to "brown things up" with glyphosate before planting.

However, after seeing that you are planting radishes with Austrian peas, another way to look at it.... plant the radishes and winter peas. When they are emerged 2-4" tall, spray with a post-grass material, such as Select, Assure, Fusilade, Poast..... or their generic versions.  Any of those products labeled for post-grass control will do a nice job in your (broadleaf) cover crop field. going this route will help you take out more of the volunteer wheat. The only down-side is if you have broadleaf weeds coming in, then you are SOL.