I've found the original A4 sheet issued by Caithness in 1998 which just shows the Water Lily Collection.
The designs for Lilypool and Traditional Pool are very similar. In addition to the pictures of the eight paperweights making up the Water Lily Collection, the sheet also shows (for those where the shape is not obvious from the picture) a small outline of the shape. Traditional Pool is a low dome. Lilypool is a disc shape (as you say like an ice hockey puk). So I'm sure your's is a Lilypool.