Nathan, If they use AWS D1.1 as the welding code, then you most likely will have a 22.5° bevel on both plates, as Dirtynails mentioned, and if they use the test coupon with backing, the root will be 1/4"(see prequalified joints in AWS D1.1:2010... "B-U2a" on page 95). You should be able to run a 2 stringer root with 3/32" without any problems. The company I was with in the past used to run 5/32" 7018s, and a 2 pass root was a bit more challenging as you have to be careful to not block access to the backing bar with your first pass.
John Wright
AWS Certified Welding Inspector
NDT Level II UT, VT, MT and PT
NACE CIP Level I Coating Inspector