What is the correct front coupler of LMSR Duchess of Hamilton locomotive?

For a while in 1939, No. 6229, 'Duchess of Hamilton' operated in a plain shop grey livery until it was given a crimson livery with 'Go Faster' stripes and a false identity and shipped to New York City for the World's Fair and subsequent tour of eastern States.

Prior to leaving the UK it was fitted with a headlamp and bell, both items I assume were to comply with Federal Railroad regulations. Although I have never seen it in a photograph, it is fair to assume that a turbo-generator or alternator would also have been required to power the headlamp.

Photographs taken at the time also show that 'Duchess of Hamilton' now masquerading as 'Coronation', also sported a Janney coupler on the front of the loco.

As link type couplings had been banned in the US some 39 years earlier, was this also a strict railroad regulation or just a precaution in case it broke down and needed a tow and also was it an original item from when it left the workshops? The fact that it operated for a few months in grey indicates that it was predestined to go to the US.

Was the Janney coupler convertible, that is to say one of the modified hinged drop-down type used in the UK by the LNER from 1938?

Since its recent restoration it now seems to have a link coupling and has also lost its bell and headlight, which is sad as it has been deprived of a part of what the world of antiques describe as its provenance.

Answers from both sides of the 'Pond' will be welcome please.