Air carrier Captain reported flying an approach that required aircraft to have a 5G filter with an aircraft that did not have a 5G filter installed. Captain stated the flight crew was confused over the 5G NOTAM and which approaches were allowed without a 5G filter.

Narrative

Taking off for ZZZ from ZZZ1 after already having a long morning getting called off reserve and de-icing in ZZZ2 the First Officer (FO) and I began to analyze the NOTAMS for ZZZ. We were flying an aircraft without the 5G filter installed so we talked about how that affected what approaches we could do. Specifically CAT II. As a high mins Captain that wasn't a factor. I dug out the company references and the NOTAM for ZZZ that listed all the ILS approach types as part of the NA without 5G filter installed. Looking at the weather we decided to just ask for the RNAV approach since it was 700 OVC. We asked for that and were cleared for it. The FO was pilot flying and I was working the radios. On final approach I believe the APP was not armed; the plane leveled off and startled the FO I looked over and we tried to re capture the glide path (GP). There was an aircraft ahead of us that reported breaking out at 400 ft. We were correcting all the way down and at min went around. They offered to vector us for the ILS; at this point fuel to ALT was a concern. I asked approach to confirm that without filter we could shoot the ILS to XXR. They were looking into it as we were vectored to do the ILS. I set us up; in the FMS and verified frequencies. They cleared us for the approach; they never clarified the question. The FO did not have the prev needles up from previous approach but we figured that out when we hit approach button and flew approach and landed. On the ground we debriefed the FMA modes and how to set up for an ILS when the approach does not auto tune the frequency and needles. Cause - New Captain and FO. Uncertainty with automation. Confusion over NOTAM and approaches without a 5G filter installed on specific aircraft. Suggestion - Clarification of the NOTAMS and approaches without a 5G filter installed.