Engine break in for new 350

[TruckintheBoro]

Continuing my questions from yesterday, as my mechanic installs my new (rebuilt) 350 engine into my '67 C10, a question about break in.

The guy who built my engine delivered it with oil for the break in and "primed" whatever that means (I'm a newbie). Today as my mechanic set to install the engine he said he thought he'd have it done by this afternoon and I asked if he would break it in before I picked it up and he said no, as an old engine it wouldn't need breaking in...just drive it "normal" for the first 500 miles. This was not what I've heard elsewhere. I called him back to let him know that the rebuilt motor includes a new roller camshaft and roller lifters and did that make a difference...he said no.

However I think the correct answer is to break the engine in by parking it as soon as the mechanic's got it installed and the timing right, then run it in neutral at ~2000 RPM for 20 minutes. Then change the oil and filter. Does that sound right?