I found my answer.
I sent an email to the Talbot company, a manufacture of bullet mirrors since 1954. The Talbot Berlin model bullet mirror was first produced in 1954 as original equipment for the Mercedes 300SL.
According to Talbot, they produced a Junior and Senior model of the Berlin and the mirror was used as original equipment on various cars 1954 through 1974. It was also sold to dealers/buyers for installation on cars that did not use it as original equipment.
That said, this mirror could have been installed on TR4.
They are still manufactured, but the price is rather steep in the $250 range for the Junior model Talbot Berlin.
Bob Beers (Vila)
Check out my website at
http://mysite.verizon.net/vze114b79/