When you find black burned oil spots on the inner aft side of the RH thrustreverser inner wall, and the hole on the oil tube on the turbine is covered with black coked oil deposits, you most probably have an oil leakage of your LPT frame oil inlet cover assembly. The oiltube itself is NOT leaking, but the leaking oil comes out of the hole above it , but it looks like the tube is leaking. In fact its a drain coming from the area under the oil inlet cover assembly. In this case, you have to remove the exhaust plug and sleeve, the cover plate and the oil inlet cover assy (looks like a crown).
Replace the o-ring and the gasket from this crown. See picture of this gasket, handle it very carefully it breaks even when you only look at it! Replace also other seals/gaskets on parts that where removed for access. See AMM 72-56-00 and IPC 72-56-01-01 for parts. Clean all coked areas, including this drainhole and the inner wall of the thrust reverser.