There were center oiler 427 FE juice cam blocks that can run hydraulic lifters. I know for certain that some service blocks were this way. I'm not so sure if any factory blocks were. So, this could be a hydraulic lifter engine.
I would not assume every part of an engine is completely broken in, just because it was ran on a dyno.
As for start up instructions, over the years I have read many a thread where remote
oil filters and
oil coolers were plumbed up wrong. If I recall correctly, some of those incidents ruined the engine. Many other threads, on less than adequate cooling, are on this site. I would certainly have instructions, if I was standing behind an engine. Even if the purchaser was a total idiot and ruined a $10K+ engine you built, everyone is unhappy, and it could reflect negatively on the builder. Yep I would have a long set of instructions, that on the one hand an attorney agreed protected me, and on the other hand protected the motor and the customer, if followed correctly.