Pre-tinning the edge launch leads would make the soldering faster, but if the pins straddle the board this could cause fit issues, so beware.  It's usually critical to have a tight fit of connector body to the board edge.  The pin to be wary of is the center pin.  They'll want a full solder joint, but that's the pad most likely to pull up with heat and pressure -- and the most critical for the circuit.  You might suggest an alternate material like Megtron 6, which is more robust for this and has good specs.