As long as you are not running the machine, having the gray fuel lines in there for the winter will have no negative effect whatsoever.
Assuming the engine is running fine right now, you are ok to winterize it with the gray fuel lines and replace them in the spring. If it is not running ok, you may not be able to fog it properly.
In addition to just replacing the fuel lines, you need to thouroughly clean the entire fuel system (lines/carbs/fuel selector valve/filters). You need to clean out all the deterioated gunk that the fuel lines so kindly provided your fuel delivery system.
If you leave gas in the lines during the winter, they will continue to deterioate during the winter and running your machine in the spring without replacing the lines and cleaning the fuel system could potentially be very bad for your engine. Just a warning! Make sure you DO change them in the spring before riding next season.