Did Jesus and the twelve preach the death, burial, and resurrection gospel?
No. Jesus and the twelve did not preach the death, burial, and resurrection gospel. They did not even believe it themselves, and John 20:9 says they knew not the Scripture that He must rise again from the dead, so they could not preach it.
Les explains from John chapter 20 that Mary Magdalene went early to the sepulcher, found the tomb empty and the stone rolled away, then told Peter and John, who came running. They suddenly realized Mary was right and that He must have indeed risen from the dead. But verse 9 makes clear that as yet they knew not the Scripture that He must rise again from the dead. Therefore, as Les teaches, Jesus and the twelve never preached our gospel as we know it; they did not preach death, burial, and resurrection, and they did not even believe any of it themselves. How could they preach it? Had they known He would rise, they would have camped at the tomb, but instead they went home and thought it was all over.