The "new" 16D with oval hole was supposed to be used in the new series, and I actually had a factory prototype of the Competition Asp fitted with one. But they were never sold by Classic to the public, and in fact 3 dozens or so of Mabuchi foam motor boxes with 24 motors each were sold to REH in 1968 with everything else. REH sold them separately until they were gone. VERY FEW received the "Classic" shield.
I can account for four of the very few that received the shield. I just bought an ebay lot that had some uncut Cuc bodies, but I really bought it because there were several of the classic versions of the FT16DBB. The motor in the cuc, one of the two in the dual motor scratch chassis and one of the loose motors have the Classic shield on. You can see the shield shaped glue stain on one of the other cans where a shield fell off. The one on the motor in the dual motor chassis is also close to falling off. None of my other examples have the shield.
Regards,
Steve C