That's an important piece; shame about the stains. First of all, using the $3,500 sale price from the most recent auction as a benchmark (that book was signed but not inscribed and the prices on abebooks are not great indicators of market, in my opinion). Actually, the total price paid with the buyers premium was $4,200, so we could haggle about which value to use. Normally, inscriptions hurt value a bit, but in this case, it is an association copy. It's interesting that Buk inscribed this to your Father in 1975 when the book came out in 1962. The inscription helps value, but would likely help more if it had been done at the time of publication. But, it is what it is.
I don't think that the inscription helps as much as the stains hurt, however. Let's say that being inscribed to the publisher brings the $3,500 figure to ~$4,000 but the stains cut the value about in half. That assumes that the remainder of the book is in generally the same condition as the copy that sold for $3,500, which is difficult to determine from the pictures (the previously sold copy was billed as near fine and your copy appears to be generally very good but with stains and a bump to the lower left corner). So, somewhere in the $2,000 to perhaps $2,500 range to a collector, perhaps $1,500 to a bookseller. I'm just thinking off the top of my head here; I'm sure others will be happy to set me straight if I'm off base.
And for the record, although this is one important piece I'd love to buy, I'm not in the market to pay this kind of coin for anything except a major car repair or mortgage payment, so I'm being objective. I think.