The GC valve configuration would backflush all components that are heavier than propylene. So if there are any heavier components, they would not be exposed to the columns. Only thing here to note is that the backflush valve timing needs to be optimized to make sure that this timing is not too “wide” to allow heavies from entering the analytical column.
You can also look at the sample system design to ensure that there are some membrane filters installed before the GC so this can prevent the larger molecule components that are not desired from entering the GC.