Hi Salman,
This gray dial version is my favorite watch to wear right now. I've been doing some traveling and it's perfect for being on the road. Multiple time zones, runs strong with approximately 2 day power reserve (remarkable!), not so costly where you're always thinking about safety, small enough (a slim 37mm) to fit under a cuff, and very fashionable. Love it.
Finding a mint, all original gray dial, Olympic tribute 6217 from 1964 has become quite difficult. But it's worth the hunt.
Yes, the white dial model is slightly less rare (but still pretty difficult to find all original & mint). I have both, but it took me over a year to find the perfect examples (and I live in Japan!).
Really, great looking watches. As the 2020 Olympics comes around, prices on these are going to go through the roof - find em while you can!
Cheers,
Matt