I listened carefully side 1 and 2 and compared how they sound differently....and here is what I found.
Side 2 - RVG STEREO side has much clearer and deeper low especially bass sound than side 1.
But with high and middle, I don't see any big difference, maybe high is stronger in RVG side but not that much.
In anyway, it is a myth. But to me, as the stamp goes, side 1 pressing is not from the RVG I guess...
My initial assumption is wrong...