Unless, of course, they
wanted to differentiate between a p.first and a div.first or somesuch...
You are absolutely correct that you shouldn't need to put units on a value of zero...zero
anything is zero - and devices/apps (all of them??) know that.
I would also remove the extra white space and the trailing semi-colon to be ocd-minimalist:
Code:
.first{text-indent:0}