Strictly speaking, no, especially if they are larger or more labor-intensive items. However, the higher a number of similar items you can donate, the better. We try to balance the gift bags so that everyone gets the same amount of items and it's easiest to do this with lots of items to choose from.
If you can't donate enough for every gift bag (148 items is quite a lot!), we love to receive donation sets in increments of 5 or 10. Single items are likely to end up as treasures or contest prizes but may still find their way to gift bags depending on need.
We appreciate all donations for the gift bags, even if it is a single item!