I got volumes 1, 2, 6, 16, 45 and 46 and they are all from the 1955 print. According to my research they value between $6 and $14 a piece. So I paid about $1.64 a piece and I could sell them for at least $6 each, as if I'm ever going to part with them, that's what a 300% return if I am crunching the numbers right.
Anyway, the most exciting part for me is that I used to borrow these books along with Trixie Belden, Nancy Drew and the Hardy Boys from my Grandma Bell. So, these books will always remind me of her. I'm so excited about seeing what other good finds I spot in the next 3 years.