Discrepancies in information on LA and Magnum series oil gallery plugs

I agree with Kern Dog that it's as clear as mud. How can it not be when you have:

• Experienced engine builders saying you must use them
• Experienced engine builders saying you don't need to
• Books that say you should use them
• A design that changes randomly including: plugs, no plugs but a solid thrust plate, no plugs and a relief in the thrust plate, no plugs and a hollow bolt
• A design that doesn't seem to make sense e.g. why have plugs if the thrust plate then blocks off the hole?

Another experience with an older 318 (poly):
No plugs.
No oil pressure issues.