Ah, some info helps alot!
HOT40ROD is right. That tag is only the body ID, not the VIN. 1574 depicts the type of body/cab. The rest is the sequential # for that body type.
The vehicle ID tag should have been on the passenger side cowl/firewall. That tag would have the letters and numbers, which would break down as mentioned above, but I see it's missing.
A number off the frame could be decoded too, but of course that's gone as well.
Further research suggests that the 1574 cab was used in a few different military applications, with their own model designations.
- ACK, ACKWX, CCKW and CCKWX followed by 352 or 353.
I'm thinking it's an early ACK-353, like one of these,
See if your body ID# can be cross-referenced against military production numbers. Try these links for some guys with military knowledge and info.
http://cckw.org/forum/index.php
http://www.olive-drab.com/
Hope that gets you somewhere. Good luck!
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