This is a semi work around method, it won't work properly when carrying multiple weapons.
For each weapon that is available in the map, make it set a boolean to true on pickup, but make sure to set the other weapon booleans to false.
Make a custom container, and make some loadout objects (one representing each weapon that you can get prior to the boots), then link the custom container to all the loadouts, then for each loadout that is linked, place a boolean filter between them (HasBurstRifle, etc), this should be a partial work around.
To place a filter, highlight the link between On Picked Up and Give Loadout, hold [Options] and then press [Add Filter].
Once the player picks up the burst rifle and then picks up the boots, they will keep the burst rifle.
The problems are:
If you have multiple weapons, expect to lose one, only the most recent weapon will be kept.
If you have Allow dropping weapon on pick up enabled in gameplay settings, the player wants their weapon back and then they pick up the boots, then the weapon they picked up and didn't want will be in their loadout.