Your cufflinks are pretty easy to date for those familiar with time period fashions.
I am very familiar with the jewellery of the 1870-1940 period, and have an intensive library of original jewellery catalogues. These cufflinks, whist one cannot pinpoint an EXACT year (since items would be made for a number of years and men's fashion items spanned longer than ladies) but we can QUITE difinately say they are classic Art Deco, and the Greek key pattern was QUITE popular in the 1925-1930 span, they are no later than that, and I would actually (making an more educated guess) put them closer to the 1925 date. Hope this is of help!
