Coolant Bottle

Im curious as to how many of you have a coolant bottle. My 71 Scamp had one mounted to the passenger side fender but Im not sure if it was factory even though its got the Pentastar on it. Thing is I dont have a cap for it so it makes a mess.

If it was not factory I would rather get rid of it but Im wondering what you guys do if you are running one? I was debating about just running a catch can type.