Just as I thought, dealer "expert" did not know what the bolt's purpose. Very smooth an adept at not answering my question until the 3rd time! Must sound like an expert!
Just an idea???
If the bolt definitely has no mechanical purpose, it's likely to be a machining tool access, probably for an oil-way or similar that's blanked closed after machining is complete.
It's risky removing a bolt that you don't know what it holds as it may be holding something inside that you cannot recover without a strip down. I would'nt touch it. It would scare me.