A return visit today gave me a view of a servicing manual on the front seat; 1969 Oldsmobile Chassis Service Manual.
And closer inspection shows that Ninety-Eight was one of the models coverered. Well done chaps! This one differs by having an after-market grille.
The full list of models being:
A???? Vista Cruiser Cutlass 442 & Delta 88 Delta 88 Custom Delta 88 ??? Ninety-Eight Toronado
So that just leaves the mystery of the hood ornament...