Yes 70 std colour was blue with the alloy tank emblem originally painted to match the tank
But the OP has a 69 according to his post
Not that it maters as any BSA could be ordered in any of the colours that were available that season , and black ws always an option for Mr Plod .
The last page of the specifications usually states "optional colours availible at extra cost "
The year matters. I only know 67's. The Factory Spares book for that year lists only red for Lightnings and blue or black for Tbolts, and I don't think I've ever seen a blue '67 Lightning. Also, both the Flamboyant Red and Flamboyant Blue were over a silver base. This I know because I stripped the original paint from my '67 Lightning.
But if blue was a Lightning option in '69, you may want to go that way; there are SO many red Lightnings around!
And yes KC, your Tbolt is beautiful!