Toyota Repair: pistons, head gaskets, toyota truck

Question
Hi,
While in the middle of changing out the head gaskets on a 89 Toyota truck Sr-5 with 3VZ-E V-6 engine I noticed that this engine had some engine work done.  I also noticed that the pistons on the Rh side (passenger side) have a L stamped into it and a notch on top of the piston facing towards the rear.  Same on other side but with R and notch facing rear.
Looking in the repair manual it clearly shows which way they go and this is not the case on this engine.
My question is can I leave this or do I have to tear down the engine and correct this?  I talked to the owner and told him what's up and would get back to him.
Thanks

Answer
Hi Paul,
I don't get into engine swap problems or engine tear down issues,
you just don't know who or what worked on it and what kind of hassles
they created for the next guy.

The only thing you can do is tell the owner its wrong and what should
be done to correct it. The manual is right. Tell him you can just replace the head gaskets but can't warranty it.

Good luck

Tim