I am always dismayed by examples of a lack of courtesy, especially when the example is based only on "a little knowledge". So dangerous.
1) Whitefriars didn't include date canes before they were asked to by the USA distributor. Date canes became the norm for weights that were sold from 1970 onwards.
2) The OWL silhouette is much later than 1970 so would normally have a date cane.
3) Dave is right that setting trials often, but not always, had no date cane.
4) A lot of very nice weights were made in lunch hours and on Saturdays by WF staff (with the full knowledge of the managers), intended for their family and friends. I have several examples where later canes were used with an earlier silhouette to make a really nice weight. Most (buy not all) of these were made without a date cane to signify that they weren't stolen stock.
This weight is therefore either a setting sample or a weight made for the friends and family of a staff member. I would put my money on the latter. the main point however, is that it is a fine and striking weight.