LARGEST ISSUE IMPERF FRANKING?

1867: MANILA to SAN SEBASTIAN, SPAIN

1864 issue of 12 4/8c x two strips of three on folded letter for 6 rate franking.
Postmark "MANILA 4 JUL 67" and arriving August 24.

Can someone check if the claim of the dealer that this cover bear the highest number of the imperf issue.