Gas tank vent line

[72WiscSub]

I ordered a new sending unit for my 72 suburban and there is no vent line coming out the top like the original one. The unit is the correct one according to the Classic parts place I bought it. I talked to a mechanic who said it is no problem not having this vent line because there are two other ones on the tank.

Do I need to have the vent line that ran to the vapor canister or not?

The line was not hooked up when I bought the truck.

Thanks