Yes. As Michael noted, many (if not most) manufacturers try to get multi-use out of their structure kits by scaling them "between scales". In addition to HO /TT, HO / OO is another common blend. The former are slightly under scale, the latter slightly over. I've also found that a lot of them seem to be slightly ipunderscale so that they have a smaller footprint on the layout. Walthers Cornerstone kits seem to me to be true to scale. A good way to tell is that if a an HO scale figure is 7/8" tall, the a standard door should be about an inch high.