HelloAlex and welcome on OTD forum!

Compliments for your watch, it looks in very nice conditions!

The corfam and the buckle seem absolutely genuine to me,
so keep them with care as not so frequent and cheap to replace.
For everyday use, yours Abel's strap is the perfect choice.

About triangles, i saw many Vics marked in that serial range (269-272), and
I noticed that one triangle seem to indicate cal.11, and 2 triangles cal. 12.
This is what i saw and there is no (i guess there will never be) official confirmation of that.
Maybe that in the period Heuer decided to clean out the drawer with the old calibers,
and the Viceroy promotion has been a great chance for doing that.

I strongly agree with Giuliano about the urgency of a new gasket,
about the date disc we have to wait for Abel's opinion.

Paolo