273 Engine year Car 1967 Plymouth Barracuda

I looked on my engine and found numbers on passenger side they are 1-20-67. Does this mean it is a 67 engine or a 68. I'm confused I had someone say if it is stamped 67 that they went in 68 vehicles. Thanks you
Here is numbers under the cylinder head on drivers side it has a 273 before these #'s

numbers on engine block.jpg