I would not pay more than $700-$800 for any D25, and that top price would only be for a '68-'70 model with the smaller pickguard. I don't think I've ever actually seen a 1968 D25. There have been some 1969-70 models out there. The '72 I bought was $550 (neck had been reset too), and this was in 2019 on a standard Reverb listing. And these all-mahogany versions are supposed to be worth more $$$.
Being that you can get a good, early D35 for under $1000 (there's been a 1971 D35 on my local craigslist for over a year at that price) ... seems like the D25 should never approach that price to me. I guess the deal would be if you want mahogany ... or the arched back. But the thing is, the arched back models are so very common that you'd probably only have to wait a week or two for more to pop up if you couldn't find one you like for a good price at any given moment in time.