Hi Tony,
I agree with Brian; the number in the front chassis casting is just the part number of the casting.
Chevrolets only carried the chassis number on the tag/plate in the cab, so if that's missing your best bet would be to see if the engine number turns up anywhere here on MLU, or in David Haydwards listings to see if it mentions a corresponding chassis number. To be honest; I had a quick look and found nothing so far. You could also check the chassis to see if a previous owner has had a number punched anywhere. What about the hictory of the licence plate......does that give you any info?
David's research can be found here:
http://hotrod.gregwapling.com/chev-t...dian-chev.html
Based on the pictures, it looks like a late 1940 built C15 cab 11 as it has the cab vents, which weren't introduced until the second half of 1940. If you inspect other details you might be able to narrow the build period down a bit more, but that's probably not what you are after in this case. I see it also has the stiffening ribs in the engine inspection panel.
regards,
Alex
Are you still running the modelling shop?