I found all the connectors that fit my S-280 from fellow collectors for the main power, but the a/c connectors were removed from the wiring system internally during demil. There is a company that stocks these milspec connectors, but they are not cheap by any means. Amphenol is the manufacturer & Digi-Key Electronics is the dealer.
There was a lot of research required, but I got it right & Digi-Key delivered the correct plug assembly which fit my a/c perfectly. You have to do your homework to match the connectors & if you do it right, you will have the correct connector.
My recollection was that the complete connector in several packages cost $65.00 shipped, but was worth it. What really bothered me was that I used to buy Gov Liquidation items & could bid on triwalls of used government wiring & connector systems cheap, but the catch was if you won them in the auction you HAD to cut them up & destroy them to get them off base. A $250 auction could win you $25 to $50k worth of wiring harnesses & Amphenol connectors, but you had to destroy them by crushing & cutting them up.