no . but when I do it's at a bad time 
You can get them from Atlas and or Kato. The plastic nuts and spacers are the same.
By the time you find a source for them you will find out that you will have to buy 100 or more.
Get a dozen or so from each and put them in your spare parts bin.
Be cheaper in the long run.
I always have more than 6 nuts, screws and spacers on hand. I very seldom lose one but once in a while one will hit the floor and I will not find it for a day or so, I just grab a spare and move along. I most of the time will find the lost part on the floor when I do a clean up!