At least one member installed the Eibach 1" leaf spring spacer block with no reported issues. That tells me the U-Bolts supplied were the same. Hopefully he chimes in.
Being a multipack I'm virtually positive a longer U-bolt is needed.
The ROW springs I put on my FX-4 required longer U-bolts. The factory single leafs are quite a bit thinner than the ROW springs, I'd bet the Tremor springs are the same.