Mangrove Jacks Brown Ale Kit - Replace Dextrose with Dark Malt?

[kickbacknbrew]

So my aunt knows that I brew regularly and decided to get me a kit, and I just had a simple question that I think I know the answer to but wanted to be sure. Its a Mangrove Jacks Brown LME kit and in the instructions it calls for mixing a half gallon of boiling water with 2.2 lbs of dextrose. (Yes, you don't even have to do a complete boil, just mix the boiling water with the ingredients in the fermenter). I was wondering if I can substitute 3 lbs Dark LME in place of the dextrose for this kit?

Thanks in advance!