No... with old frames in classic steel some manufacturers do center to center, other ones do center to top (top tube), then around 90 something the thing started to get weird because some manufacturers like moser started to manufacture shorter frames and bikes with a 1 to 3 cm neck over the top tube then putting some average size engraved in the BB shell (my last steel found is like that).
With sloping the thing was even worse so basically now with sloping frames what u have to do is look at the virtual or effective length of the frame because the decal or what the manufacturer says doesnt even match sometimes the size of the seat tube.
Somebody mentioned the stand up, well that thing doesnt work that much because not all the bikes have the top tube at the same level, u have road bikes that have higher or lower BB shells too, and I dont even want to start talking about a track bike because the stand over is even higher. So you can have a 53 frame and a 55 frame with the same stand over height, you pick the 55 (if your real size is 53) and you could be picking a frame too big, or what happens with hipsters, a hipster that uses a 56 road frame will pick a 54 or a 53 track frame based in the stand over size, track bikes can have the bb shell like 2 cms higher than a road bike, top tube is higher also, then there u have it, they always pick a smaller track frame because of this weird idea that the stand over is the way to go.