Not specific to 280. But I load for, or have in the past, 308, 30-06, 280, 338/06, 7mm Rem Mag, 300 WSM, and 6.5 CM. In my experience Winchester and Remington brass is close enough that I've found load data to interchange. I still separate my brass and will load in batches of only Winchester or only Remington. I've never noted enough difference between nickel plated and brass to matter either.
It would still be a good idea to back off the powder charge a bit if you have a load you are using any time you change components such as brass or primers. Especially if the load you're using is at or near max. If you're using a mid-range load that may not be necessary.
FWIW I also use some Hornady and Nosler brass. It has also proven to be close enough to use the same data. The only brass I've found where I had to significantly alter my powder charge was with military surplus 308 brass or Federal brass in any cartridge. Not implying Federal brass is bad, just that I needed to reduce my powder charges slightly when using that brass.