The bottle in the b&w photo is by Paul Ysart, which would tie in with the museum description of post-war Monart. The shape is similar to the Salvador / Vasart bottles but the important point is that it is the shape plus the striping in the neck & well (and the stopper shank) that mark bottles of this type as Salvador / Vasart.
Other than that, without getting into cane analysis, it is usually the size of the bottle and stopper that is the next best indicator of Paul Ysart bottles which tended to be larger than those of Salvador / Vasart. But it's not quite that simple. Sizes vary within both Paul's and the Salvador / Vasart bottles.
Another point is that (probably) most Paul Ysart bottles have a clear neck & well (and stopper shank). But there are several known that are decorated in those sections. However, I have never yet seen or heard of a Paul Ysart bottle with the striping as in the Salvador / Vasart examples.
And although the majority of Salvador / Vasart bottles do have striping in the neck & well, there are some that have clear glass in those sections. Some folk have thought these must be by Paul Ysart, but the canes (and other features) show them to be of the Salvador / Vasart type.
The PY doorknob is a good example of something that is rarer than his inkwells!