Old photo dating - man's hat may be a clue?

[Arvanitakis]

Another Q - How late could the photo potentially have been taken (considering it's an ambrotype + fashion)?

I suppose it could have been my 3rd g-grandparents but with a later child - say in 1867 when they would have been 25 (man) and 27 (wife) - or 1877, aged 35 (man), 37 (woman)?

[jim1]

I've not seen an ambrotype later than early 1860's.