Your LBS owner probably can't get the NOS parts that might be needed to refurbish the bike. That's why he wants to replace everything.

NOS parts are available at a few specialty sites online. The particular parts you'd need may or may not be available. Obviously bike shops generally will not want to install parts that you bought yourself, but if you talk to the wrench ahead of time, they may be willing to (1) let you know what you actually need and (2) install it if and when you find it. Unfortunately it doesn't sound like you have the kind of relationship with these wrenches that it would take to do that.

All the bearings will need to be re-packed, but that's not a huge deal. I don't know why the BB would automatically need to be replaced if it's got that few miles on it and wasn't ridden loose.