OLD is the over-locknut-dimension. Meaning the distance to the outside faces of the locknuts on the hub. In the ideal world regarding rear hubs, the OLD will match the rear dropout spacing of the frame. Your frame has, for all practical purposes, 126mm rear dropout spacing, which was common on bikes with 6 and 7 speed rear clusters for quite a few years, because the OLD of these hubs is 126mm. If things are off a millimeter or two, it's no biggie. In regard to the 130 OLD hub comment, what he's saying is that it's not a big deal to jam a 130mm OLD hub into your frame that has 126mm rear dropout spacing. 130mm OLD hubs are the modern standard on road bikes, and have been for quite a long time now.