Don't let price interfere with buying the book. You're highly unlikely to find it cheaper than $50, and that price has been seen only once in recent times. Expect to pay around $75. It's worth every penny, and more.
Because I was involved in refining, and was not a benchman, I have no history with Gesswein, but they are an old established business, serving the jewelry industry for nearly 100 years now. I wouldn't have any reservations about doing business with them. I feel confident that I am not providing a risky source. Had I not had a ready source for my supplies in Salt Lake City (melting dishes and related items), I'd have gladly done business with them.
I'm going over there tomorrow. I'll find out what years they have on hand. I'm an IPMI member now so I may be able to get a better deal for you if you are interested.