The earliest of the 1953 CJ-3B models were produced in 1952, so I would expect this should have a very early serial number.

“The 1952 CJ3B was the first year of the CJ3B series and this is one of only 2360 (amc records) that were made in 1952.
Pros:
-) Runs Strong
-) Brakes gone through and work great
-) Shifts smoothly
-) Clean title
-) 4wd works
-) Solid floors
-) New fuel lines
-) Carb cleaned
-) Original F-134 Motor
-) Original T-90 Transmission
-) Original Dana-18 Transfer Case
-) Original Frame and Body
-) No rusting through
-) Body-Off bed line and paint
-) Good Glass

Cons:
-) Needs a clutch (willing to fix)
-) Body has bondo
-) Needs a battery
-) Windshield frame is bent a little (again, willing to fix)

Willing to deliver to states near Wisconsin!
Price negotiable, make me an offer.
Cash only.”

https://greenbay.craigslist.org/cto/d/1952-cj3b-willys-jeep/6440008484.html