[NorthOfBoston]

Hey all, new to the site, so forgive me if this already has a thread somewhere.

I've recently gotten back into collecting, after about 25yrs away from it. I've sent a bunch of my cards to PSA, as well as made several purchases of PSA graded cards. I've read the thread on this site regarding the changes over the years in the PSA flip, and was curious: how tough is it to find a graded card with the original flip? The style with the slashes through the zeros. It doesn't seem as though I see a lot of them up for auction, so I'm wondering how rare they are, as well as if they add any actual value to the card itself?
Any info would be greatly appreciated. Thanks.