Yes, It is very true! Here are some articles...
Feds Hide Social Security Deal With Mexico
Feds Hide Social Security Deal With Mexico
Social Security 'Totalization'
Examining a Lopsided Agreement with Mexico
Center for Immigration Studies
Seniors group unearths immigration bill 'loophole,' warns of drain on Social Security
Seniors group unearths immigration bill 'loophole,' warns of drain on Social Security (OneNewsNow.com) (broken link)