Does this receipt of my application I-140 guarantee me to prove to the US custom of my employment?

Question

My concern was I was interrogated at the US border taken my fingerprints and picture., fortunately, I wasnt banned though..but according to them, if I want to come back US, I need a proof of my employment.
I have a canadian passport and Im planning to go back and try to enter US but Im bringing with me the receipt of my application I-140
but I have doubts whether this receipt is enough to prove to them of my employment and Im safe enough to enter US without questions.

Answer 1

That is really a question you may want to ask Customs & Border Protection.

As a USCIS Customer Service Representative (aka, Im one of those people who answers your call when you call the Customer Service Line) we are told that yes, the receipt is sufficient evidence. However, I have received calls from very upset non-immigrants & immigrants alike who tell me that they were interrogated & in total, disgusted, with Customs & Border's accusations & investigation once they crossed. So, to avoid this... CBP's telephone number is 1-202-354-1000. Their website is also http://www.cpb.gov if you would like to consult it first. They will give you a definite answer.

I hope I helped out a bit, if you have any questions, feel free to e-mail me.