The mark is in the mind. The hand is symbolic of labor
Revelation 20
and who had not adored the beast nor his image, nor received his character on their foreheads, or in their hands; and they lived and reigned with Christ a thousand years.
There does seem to be more than one way to worship the beast but I have no doubt that if our society can do it they will put a computer chip in our right hands or in our foreheads, in the time of the eighth beast.