I agree to a point. Last year looking at a different 70 340 swinger for a different friend, we went to see the car. Young kid didn't know much. No fender tag. He was told it was all original. Previous owner had it a long time. Vin tag on the dash said it was a 340 car. Rad cradle #'s were covered up with fresh paint. Crawled under to check the block and trans. Again volia, #'s matching ! Kid had no idea. Both my friend and the seller were looking at me waiting for the news. Tourque boxes were present, coin on the K frame, sway bar and disc brakes, rally dash etc. all present, wrong rad, no shroud, fuel injection, no heater box, visible patches in the trunk floor. Car ran and drove well. Had a lot of little things left half done or shotty workmanship. Recommend a strong pass which was taken. Back to the number thing, I looked at both my friend and seller and asked "who am I working for"? Before I got an answer I blurted out "it is a number matching engine, trans and vin tag". Some might think that was stupid. Usually it's a exercise in a battle of wits. Neither party total trusts the other. When one is honest and it's proven, then possibly when I give my reason for my offer (if even interested) it may or may not be accepted as honest too ? You catch more flies with honey than vinegar. The seller appreciated the education and eventually we told him we were going to pass.
Eventually found my friend a very nice original paint 67 Coronet R/T for a few $$$ more.