Will these bolt straight into my truck without modification?

Yes. These mount at factory attachment points, so no drilling or bracket fabrication needed. Unbolt the old units and bolt these in—basic hand tools only.

Do I need to transfer my bulbs from the old headlights?

Bulbs are not included with these assemblies. You'll transfer your existing bulbs from the factory headlights into these new housings.

What's the return window if these don't fit or work as expected?

Test-fit before final installation. Once power is applied and the housings are sealed, returns become complicated. Verify fitment on the vehicle first, then commit to wiring.