Hygrometer Calibration Kit

I purchased a Boveda one step calibration kit for the hygrometer in december and opend it on the 23 of December, it states on the kit it is good for 3 months. So 3 months would be up on the 23rd of this. I bought an Xicar hygrometer today and stuck it into the bag. I am going to leave it there for three days to see where it is. I guess what I am asking is does this kit really expire? I mean it is just salt and water I am sure it is not bad right now or by the 24 wich will be three days.What do you guys think am I good?
Thanks Josh