Air carrier Captain reported a gate departure delay due to a missing DG acknowledgement code missing on the NOTOC. After further investigation the DG acknowledgement code was located and the flight departed.

Narrative

We received the NOTOC document and this was my first time seeing a laser printed copy of the NOTOC and I expected a matrix printed copy with the DG (dangerous goods) acknowledgement code for the ACARS. As we approached departure time I was searching the laser printed NOTOC form for the DG acknowledgement code to be entered in ACARS. I passed the document to my First Officer (FO) who also searched the document with no luck. Finally; we got a hold of the gate agent; who didn't know how to find this DG acknowledgement code as well. The gate agent got on the walkie talkie with Operations; while I contacted Dispatch via phone for some guidance. Finally; they provided the DG acknowledgement code over the phone; but I said that I would like to have the document printed with the DG acknowledgement code on and the gate agent ran to get it printed and came back with the same laser printed document we already had.With help from another agent; we finally managed to locate the DG acknowledgement code in the top right corner of the document.We departed late on a right start flight. When we reached cruising altitude I looked up the NOTOC form in the FOM. It was rightfully listed with matrix and the laser printed copy of the form and where to locate the DG acknowledgement code.When departing out of a critical terrain airport; with special EO (engine out) SID in early morning there is really not much time to try and find this information in the FOM. when neither myself; my FO and a gate agent could locate the DG acknowledgement code on the laser printed document I was convinced that it was the wrong document I had received.May I suggest that the DG acknowledgement code on the laser printed NOTOC be significantly enlarged along with a thick line box or similar to draw attention to it.This number should be easy and straight forward to locate and it was not the case.