[Pazuzu]

Technically, yes, they are one time use items.
Realistically, no.

Since (I presume) you're going to be streeting this truck, or very mild trail riding, they should be fine re-used. If you're going to be doing hard offroading, then you should replace them.

The other problem is that add a leafs make the leafpack thicker, and the stock u-bolts might not be long enough.

I would run what you have (if they still fit), and keep an eye out for longer ones that are designed for Tacomas with extra leaves (I know some company somewhere makes them). Buy them when you find them, and replace your stock ones at that time.