is it correct to make the cheque out to department of homeland security?

Here is what the Instructions for I-751, Petition toRemove Conditions on Residence says

2. Make the check or money order payable to U.S.Department of Homeland Security, unless:
A. If you live in Guam and are filing your petitionthere, make it payable to Treasurer, Guam.
2. Make the check or money order payable to U.S.Department of Homeland Security, unless:
B. If you live in the U.S. Virgin Islands and are filingyour petition there, make it payable toCommissioner of Finance of the Virgin Islands.
C. If you live outside the United States, Guam, or theU.S. Virgin Islands, contact the nearest U.S.consulate or embassy for instructions on themethod of payment.
NOTE: Please spell out U.S. Department of Homeland Security; do not use the initials "USDHS" or "DHS."

That is what I have done for all petitions we have filed...K-1, AOS and lifting conditions....no problems

yes, you do!!