Farmall Cub

I have a 69 cub lo boy but I am thinking the engine is not, because it has a reddish color to it...so I a thinking someone swapped an engine from a 185 into it....if that is the case where could I find an engine badge to see maybe year of the engine?

http://www.tmtractor.com/id/id_001.htm

Try this page. Look up engine serial number location and the engine casting code. The engine casting code will proved a general date.