Gday Tasos
Jim is spot-on for the time frame you have in mind... They are two of the most accurate kits to date.
The M4A1(75) [the one with the rounded one piece cast hull] was in service at this time also, although it is tough finding the old Dragon kit, and it needs a few tweaks... Ok a lot!
The M4 (as well as the M4A1) was one of the most prevalent for the US army, and there is really only the Tamiya M4 on the market, which has it's own inaccuracy issues...
If cost is no object you could have a look at
www.formationsmodels.com They have the M4A1 amongst others...
Interior detail is tougher, though there are definitely kits out there... I know Verlinden make the engine, Tiger has great hatch updates, and I can't think of who makes the interior, sorry!
I reckon your best bet would be an M4. Get the Dragon Sherman MkIII kit, and then the formations update I think it is $15 USD, and you will have the most accurate M4 on the market for the price... (Unless you go full resin!)
cheers
Brad