[Okay, thanks, up-dated. Admin.] Class II stone, not Class III? Canmore states it is Class II, and seems to be an early example at that, c late 7th-early 8th century.
However, it might be worth noting that the traditional classification of the 20th century is under review, and seems much more complex. https://www.cambridge.org/core/services/aop-cambridge-core/content/view/4F09B9C943A1C29F226591A20BEC5248/S0003598X18000686a.pdf/development_of_the_pictish_symbol_system_inscribing_identity_beyond_the_edges_of_empire.pdf
Something is not right. This message is just to keep things from messing up down the road