I pick up a collection. In it is a Winchester Arms Collectors Association Model 70 XTR Featherweight Super Grade .257 Roberts. I can’t find much about them. I have found that there was 170 made. Not sure if you can get a letter on it. If so how would I get one. Also is there any were to get copies of the paper work to go with it. Will try and add pictures it is a very cool Model 70. Any help with info and value would be great. Thanks