Real Joy Hill letters?

It's not easy to read the letters. I'm in two minds about them, myself. On the one hand, it would seem fantastic to suppose that someone could fake letterheads of A&U, and Help the Aged. On the other hand, I can't imagine anyone English spelling 'cheque' as 'check'!

I was also curious about the publishing date on the book. I would have thought that would have been after 1973, probably 1975 or there abouts. Anyone else have a better date? The signature looks good, but something doesn't seem right. I also agree on the check vs cheque, a little unusual at best.

The UK spelling of cheque is used in the letter on the left, so I agree that it is very surprising that the US spelling check is in use in the right letter. I am sure that Joy Hill would not type cheque as check.

There is also nothing really tying these letters to this copy of the book, the letters refer to a signed US copy but they are reproductions and how do we know it is this copy that is referred to?