Johnnie Walker Red Label Vintage bottle - looking for valuation

Hi, I just acquired an old Johnnie Walker red label 1.75L bottle, sealed in its original carton box, which was never opened.
My grandparents brought it from abroad in the 60's I believe (there's no date on the box), and I'm trying to see if it's worth anything significant.
Thanks for your help

[Jojo]

Hi there and welcome to the Whisky.com Forum! While we can't place a value on your bottle of Johnnie Walker, we can try to have it dated for you. If you would like it dated, please also post photos of the bottle itself. For a value, you can try McTears.com or Bonhams.com.

Does it matter to the price if the box is unopened or not? because it was never opened and I don't really want to tear the carton.
Anyway, here's a photo I found online:

[Jojo]

If it's not opened, don't open it! We will see what we can find out regarding date based on the photo you provided.

[Jojo]

We weren't able to get much information on this carton - but Diageo tells us they're pretty sure it was introduced in the late 1960s /early 1970s.