i would say three line coo a little rarer .there is two versions of three line coo the 1977 is in different positions.allso the rivet is either large or small.
ta,
i was wondering whether the 3 line was an earlier type?
not sure which 3 line it is, large or small rivet as i have no other 3 line to compare it to.
as i said before the 1977 can be further down leg.looking at rivet on these ,it could be same size but in different position.on two line one's rivet is a definate large or small size.