Kirk in the teaser says the ship has been missing for "over two centuries". Later he says the recorder marker they recovered was launched "two hundred years ago". That's the extent of it - but it doesn't seem to support the 170 year interpretation, as the "over" part is quite explicit. Probably we should be thinking in terms of 202 or 207 years or something like that...
Well, we know they still hadn't gotten anywhere close to knowing when their show was happening. But...
'Over two centuries' ...
Century means 100 years, but also epochs of time.
If it went missing in 2065, stayed missing through 2100's, and then appeared again in 2260, that's a mystery "spanning 3 centurys" of 'history', but less than 200 years, or 2 centuries, of calendar time. So I think colloqueally he'd say over 2 centuries since he knew it was lost in the 21st and now it's the 23rd. And if it went missing 170-199 years ago, I'd still say 200 years ago, and I may have said 'for over 2 centuries' because of the funnyness of how we like to group centuries not just as units of measure, but more like check-marks of history. The SS Valient's mystery spanned over 2 centuries.
We can re-master it again and just find Kirk saying 'almost' somewhere, and re-dub it.
"If you need a holodeck to make an interstellar starship on the bleeding edge of the unknown
interesting, something is seriously amiss."
- Straczynski & Zabel