First off KO did not use protector till 26,***
, and if it is used, I am not clear if it extends up to the cover.
I forgot to che ck serial number range for the washer ,but there were 3 different covers in use by the end of KO...approx 44,8**.
I believe my 72 had washer and no protector.
Checked my book that goes to K1 ..washer came into use at #44,806.... Dont know till when ..maybe end of K2.