I would guess and say that is a partial vin from a 4x4 k code not sure if gm used k in other vin numbers
Block casting numbers are at back top of the block
To varify 327 check block casting code and also check crank casting code as well
Example 350 casting code block 3970010 with a 327 casting code crank
You can get either a cheap inspection camera or use cell phone to take pics of the block casting code and depending on casting number further inspection would be needed
Like my bros 327 with 3970010 block casting code its a 350 block pulled the pan and checked the crank casting code next came up 327 truck crank
https://nastyz28.com/sbchevy/sblock.html
https://m.youtube.com/watch?v=5COyGWqJsVE
https://www.mortec.com/location.htm