273 or 318?

So I used a scotch pad and revealed the full stamping. It is in fact a 273. The full number is PM273R 28490556.
I’ll have to clean the block up at some point to find a date code. I still suspect it’s not a 69 because it’s not red but I saw a low mileage original 69 recently with a 318 that was also turquoise so maybe they didn’t paint all the 273 and 318’s red in 69 as I had read.