If it's NW-metal, then the NWA section of the WorldPerks earning guide should apply:

Northwest Airlines and Northwest Airlink
Elite Qualifying Fare Classes
Elite Qualifying Miles at 150%: P, F, J, C, I, Z, Y, B
Elite Qualifying Miles at 100%: M, H, Q, V, L, T, K
Elite Qualifying Segments: P, F, J, C, Z, Y, B, M, H, Q, V, L, T K

Only if it's CO-metal, does the CO section apply:

Elite Qualifying Fare Classes on Continental-coded, Continental-operated flights (except where noted)
Elite Qualifying Miles at 150%: J, C, Z, A, D, Y, H, R
Elite Qualifying Miles at 100%: K, M, N, B, V, U, O, F
Elite Qualifying Miles at 50%: Q, I, S, W, T, X, L
Elite Qualifying Segments: J, C, Z, A, D, Y, H, R, K, N, B, V, U, O, F

... my $0.02.