strange dates

[clopo]

Looked at a set of pristine exhaust manifolds and smog tubes tonight for a 68 Z. The casting numbers were 3892683 LH and 3872730 RH but the dates were L-20-8 and L-16-8 Looked like they were taken off a new car.Can anyone explain the dates?

[wheelhop]

Wouldn't that date be for a 1969 model year Z?

[clopo]

According to Chevy by the Numbers and Mac Neish's book they are 68 only

[nuch_ss396]

L-20-8 and L-16-8 dates would have to be service dates if
JM's book is correct. L-68 is Dec 1968 which would qualify
for a mid-year built car. If the casting numbers are
1968 only, then they must be service dates.

Nuch