Are any banks out there filing with the new SAR form yet? We are in the process of testing our new system for it and are debating the field PRIOR REPORT DOC NUMBER. The only way to obtain this number is to dig into a text file in the FinCEN acknowledgement email. I'm interested to know what other banks are doing, or planning on doing, with this field. You are allowed, per FinCEN guidance, to fill this field with 0's if you don't have that number.

That's true, but that only works when the original SAR you are correcting, amending, or continuing was filed on paper. If your bank filed the original electronically it will be apparent to FinCEN, your regulator, and any third party reviewer that you do have the number.

We use the new SAR. As for the DCN, we download the "Track Status" page as a CSV and save it to a spreadsheet. When a DCN is needed it is much easier to find it this way as the SAR filing name is included.

I file electronically and had to re-file and did not keep the DCN's. When I called FinCEN I was told no problem, just enter zero's.

I'm not certain you got the official response to that, but I'll wager your regulator will say the DCN is part of the form and subject to its 5 year recorde retention requirement.