YH wheel code help

[GN1220]

I have 4 YH code wheels that I'm told are a Z/28 code. Can someone break down the date codes for me please?  Going to be selling them and would like to list them with as much info as possible.
1. K-1-9         2 YH
2. K 18 12  18 YH
3.1-9 10      30 YH
4. K 18 12   17 YH

[HOT3O2]

1- I think your missing the month.
2- Dec. 18, 68
3- Oct. 30, 69
4- Dec. 17, 68.

[GN1220]

After more cleaning: K-1-9   27 YH

[GN1220]

Thank you for the help. Where can I learn how to decipher these codes?

[69Z28-RS]

The first digit for Chevrolet rallye wheels)is 'K' for Kelsey

The second digit is '1' for Chevrolet

the third digit is the last number of the YR ('9' for 1969)

the next numeral(s) (one or two digits together) represents the MONTH (1 for Jan, 12 for Dec)

The next numeral(s) (one or two digits) represents the day of the month (1 thru 31)

The last alpha characters represent the application (where/when was it used).. 

This archive page provides the information:      http://www.camaros.org/suspen.shtml#Wheels

[rszmjt]

The width & corners of the cooling slot holes in the K19 10 30 wheel should be smaller I'm guessing.