What scale? Plastic? The only 1/25th plastic one is the old AMT that has been around for decades. It is based on Ohio George Montgomery's coupe and has several severe body modifications which make it difficult to convert to more stock body configuration. The fenders are trimmed, the hood has bulges to clear the Ford 427 SOHC, the top is chopped, etc. They also made a van with the same front end problems but the van body is more stock. Interestingly, most die-cast including the JL 1/87th scale gasser series, the Micro Machines models, etc., the Hot Wheels hoodless toy, all use the same Montgomery prototype which tells me they simply chopped the AMT body rather than develop their own pattern from scratch.
There are two common 1/25th die cast, original pattern models out there. One by First Gear (most abundant version is the CarQuest promotional candy red one that is all over ebaY) is very accurate and maintains the stock sheet metal configuration. The other one (Racing Champions, most recognizable in the Hot Rod promotional series) is not very well proportioned. They also make a '42 coupe that is poorly proportioned.
Other than that, there are a few resin bodies out there most of which are poorly proportioned and usually pro-street bodies that aren't very interesting. There is one resin body (I have one and will look up who made it) which is incredibly accurate and totally stock. One of the best detailed and accurately done model bodies I have ever seen from any manufacturer for any car. Don't have a clue how he did it in resin, let alone styrene or die cast. He even sold a set of stock '33 Willys clam-shell wheel inserts so you can make a 100% stock '33. Great basis for any type of Willys 'cause it starts out dead stock so you can modify as desired.
Here is a photo of the Mill City Replicas
'33 Willys w/ seat and wheel inserts. Don't know what the wheel inserts fit but a good guess is old AMT Model A kit tires and wheel backs. I have a few hundred of them in my parts bin so no problem! They don't have a web site and may not even be in business but I did get a reference for them on a web search. In addition to this car they also make (made?) a '34 coupe, '33 phantom roadster, '33 4-dr sedan, phantom '33 sedan delivery, & phantom '33 pickup. You may think it is a mistake to call the latter two phantom body styles but Willys didn't make sedan deliveries or pickups until '35-'36 which had different hoods from the '33. You see '33s around but people did a front end swap to get a '33.
MILL CITY REPLICAS
PO BOX 40
CARVER, MN 55315