Sp2 updates WinPE to version 5 which is based on Windwows 8.1. The default WinPE in LANDesk is the 32 bit one so if you havent changed anything then you need 32 bit drivers.
You mention video drivers but for WinPE you only need storage and network at most. The new WinPE has a very large driver store so I would test your hardware before adding any drivers as you may not need many if any.