First time visiting question - 3100 for sale

[eighteenninetytwo]

Hi all.
I normally frequent the blazer forum, but close to me there is a 1953 3100 for sale. I know that the owner really needs a quick sale too. Frame seems OK, body a bit rough but not crazy though one rust through hole behind passenger door.

Engine is blue (replacement?) block number clearly visible. Should the block number be anywhere else to see if it is original? And anything I should definitely beware of?? No pictures available right now I fear.