You say the LPs are in great shape. I assume you mean they look good on the surface. I've purchased many LPs that are 50+ years old and looked like they had never been played. Only to find they sounded terrible, Even after Ultra Sonic cleaning. I think somtimes they are just worn out, even though they look great to the naked eye. It's a gamble with any LP that old. IMHO.
RCA Victor records' quality
I just bought three old records, I guess all the way from the mid and late 1950s. They each sound very harsh and "shrieky". I wonder if it's the way they were meant to sound? The records themselves are in great shape.
Should I rely on tone controls or is it how music was produced and published back then? Namely Elvis' first few albums?