I am not sure what Guatemala visa has to do with it, but the CBP stamp contains the 3-letter abbreviation of the port of entry. Below is an example where to look for it:I am filling out the N-600 for my adopted son and cannot remember the Port of Entry we used in 2004. It was either IAH airport in Houston or DFW in Dallas. Is there anything in the Stamp put on my son's Gautemala Visa that would tell me this?