It seems to me it's not
Now I have 5 bottles when I load the game. Actually I have all items (5 bottles, 5 jars, 5 sticks) but none of them are displayed in the inventory (I throwed all of them away before saving). When the save file is loaded Tilo is armed with bottles and there are no bottles, no jars and no sticks in the indentory. After that if I throw 1 bottle away 4 bottles, 5 jars and 5 sticks apear in the inventory. So I think the number of each item is being set to default (5) after loading the game.