Until Federal law is changed, it still supersedes state law. While it is unlikely they will waste resources in a frivolous attempt to bust every person who uses marijuana in those states (they don't now, as any amount is a violation of Federal law and they never prosecute small time offenders), IF you had the misfortune of getting caught by a Federal officer and you had bought a firearm recently, you very well could be subject to an additional charge.
My advice is that until, and if, they change the law at the Federal level, you would be wise to lay off the left handed cigarettes.
I prefer dangerous freedom over peaceful slavery.-Thomas Jefferson
I would rather die on my feet than live on my knees.-Euripides