5BK114285 - your decoding looks good
5= kansas city --- yes, Kansas City, MO
BK= 1942(early) and 1944 to 1945 = 1942 Light Delivery (a Light Commercial Truck)
Supposedly, no commercial trucks were built in 43-45, but an earlier truck might have been sold/registered in those years
11= November --- yes
4285= 3284th vehicle (4285-1001=3284) --- 3285 (starts at/with 1001, just subtract 1000)
If you have the original engine, the engine serial number would have a year code on it, I think. I do not have info on WWII engines, but other members here have that info.
http://www.1954advance-design.com/chev-specs/1942-candt-ser.pdf
