Ken,

Either *may* be acceptable for pre qualified wps

Do make sure the brand of wire (yes this is brand specific) will provide the properties your wps requires with the shield gas you select.

Also note wire feed speed and voltage requirements will vary with different gasses and that same FCAW wire.. You should be able to get a manufacturers data sheet that provides guideline parameters for wire diameter travel speed, position and approximate deposition rates.

Here is an example of a Manufacturers data sheet for an E71T-1 FCAW wire that can run both shield gasses
http://www.hobartbrothers.com/pdf/datasheets/Triple7.pdf