I'm fairly sure there was no Maserati involvement. The confusion may be due to the Maserati Birdcage which Penske had driven the year before, which was also named the Telar Special (he had sponsorship from du Pont and I assume this was one of their brand names).
This Cooper is chassis CM/2/61, one of three built in this style, and this was supplied to Penske as a rolling chassis "sans" engine and gearbox. All the records on "a certain site" claim the car was Climax FPF powered. Most reference books claim that this body style was selected by John Cooper especially to appeal to American taste and thus sales.
