Rogue Dead Guy Clone Kit: Should I Partial Mash?

I have the Brewcraft Rogue Dead Guy clone kit. Its mostly extract (5# DME) however the grains included are Munich and Crystal. The directions say to steep for 30 minutes.

Grains:
1 lb Munich Malt
.5 lb Crystal Malt 40L


-Would there be any benefit flavorwise, to mashing the grains instead of just steeping?

-I also have 1# of flaked barley sitting around. Would mashing that along with the grains signifcantly change the flavor profile of this kit?

Munich malt must be mashed- however it can convert itself so if you "steep" it you'll be mashing it.

I wouldn't add the flaked barley, though- it'll cause a hazy beer and I think be out of place in the Dead Guy.

Thanks. I was concerned about it being too thin in mouth feel with only 5# of DME. I may add a little maltodextrin instead of the flaked barley at the last 15 min into the boil.