N Male (Plug) connector stainless steel with 13/16" nut

Hello, I need to find a quantity of 5-10 pieces 50 ohm N Male connector, mounted on a 4 hole 1" (25.4mm) flange. The connector must be passivated stainless steel (not brass) and must have the 13/16" hex coupling nut (not knurled). The connector is fitted to a naval radar, so has to be very high quality.

Omni-Spectra (MAcom) made these parts under the number series 3651-XXXX-XX, but this series is obsolete. I have found Americon parts listed under the same part numbers, but they are brass with knurled coupling nuts, which I cannot use.

If anyone has such a part or could recommend a supplier, I would be very grateful (I have been looking for some time!).

Thanks