Yes, it is by Paul Ysart and made at the Moncrieff Glassworks in Perth, Scotland. It could date from the 1930s or mid-1940s up to 1962.
Does the clear glass show any particular tint, such as quite dark, very dark, purple, yellowish or is it quite clear? The tint, or lack of a tint, will suggest the likely date period.
As John has said, a couple of other photos would be useful. The base can be shown at a slight angle and the profile should be "side on" and taken against a plain white background.