Well, no I don't.
The early AC Bucklands had a cutaway door shape, and the later had the through-line as this one has.
I can't recall when the change happened and can't be bothered to look it up. I would say post 1950 (well I did say) but there would be little to say if it were 1950 or 1953.
In period it would not have been called the Mark I for two reasons:
nothing is ever the Mrak I until it is superseded by the Mark II (unless you count Popes called John Paul
)
The earlier version (as described above) would have been the Mark I.
Yes I
have seen it advertised as a 1952 Mark I, but that doesn't mean the advertiser is right!