TEXASSP, I was fortunate to find my lost convention cars without ridiculous NETCA collectors prices!
Yeah,not so much on a wide variety of O, but happy not to have to look for these.
i usually don't do collector pieces but these McGuiness New Haven unusual box cars look great behind my NH EP5. I believe that the cars were reissued at one point (k line) without the convention markings and the patterns and graphics were inverted. I had them too back in in early 2000.