Don't think so.
First design proposal came 13 June, 1940 (OCM 15889). Pilot turrets (on M2 chassis) were first demonstrated 20 December, 1940. Production drawings were 90% complete at this time (including the Grant - whose characteristics had already been established).
Initial design was completed 1 February, 1941. First pilot moved under its own power, sans turret, 13 March 1941. It arrived at Aberdeen Proving Grounds where the turret was installed on 21 March.
First production pilots did not arrive until 5 May, 1941.
The Grant configuration was established by L.E. Carr during the summer of 1940, to include the British standard 54.5 inch turret ring. Crew space was expanded, with more headroom, plus the shifting of the radios to the bustle.
On that last note, I hope the improved "efficiency" of the British version is modelled somehow.
[ October 22, 2003, 10:32 PM: Message edited by: Shortround ]