i have indeed read both and i think you're applying it to different fields of work.

rawls did indeed have the veil of ignorance idea. but he applied to to legislation and public policies. rawls was not interested in why people date one another, but in what laws are just.

becker went the opposite route with his dating piece. he wasn't concerned with politics in the usual sense (surprisingly), but with the everyday lives of people.

to be absolutely clear, you're quite right that they're both "rational choice" theorists. but rational choice was not an idea original to either man.