If a lifter leaks around a worn bore how does it build the proper pressure to pump up. They all lose pressure from one bad bore . Out of spec lifters and bore on a fresh motor will cause lifter clatter. I am not saying the lifter assembly wouldn't . But when you start a engine and it takes a long time to pump up the lifters it is usually due to pressure loss. This could be at one bore.
Truing the bore is a must if a cam lobe is wore . This is usually due to a lifter bore not in the correct alignment of the center line of the lobe preventing it from spinning which causes wear. If you tore that block down you will know if there is a problem. If there is not and the bores are wore then just bush them. If you didn't tear it down but bought it bare . I would suggest truing the bores. Why take the chance.
We just received a New aluminum block from DART . My son had to remove all the sleeves and re machine the block correctly. I would never trust installing all my new parts in a new block without checking everything. Pro crank from Scat over 28 grams out of balance. Most would just throw that crank right in.
There are different reasons for failures. What I am saying is never skip what you could have prevented. If My son says remove the tube or install the other side. I would listen to him. We get several engines here from other shops that fail. All types of failures and it is usually caused by assumptions. Things that were assumed to be OK or from builders that don't have a clue. When a engine fails there is a reason.
If you are freshening an engine that you tore down and everything looked good as far a wear patterns then you know what you have. Don't assume an empty new or used block you did not know its history of is good to go as far as being machined properly.
I think everyone agrees with you that the bores must be correct to have a proper valve train especially when using any type of hydraulic lifters.
The current issues that are being seen in the field is that the affordable after market lifters are of poor quality thus causing the majority of the leak down issues.
I can speak from personal experience that you can have perfect bores and also have hydraulic roller lifters that rattle like a *****.
After market parts are not what they used to be, most of the componets are sourced off shore where the provider of the componets have no control over the quality of the process and/or the materials..