Welcome from Pennsylvania. I cannot find any reference to a Letter in the final place of the serial number. A photo of the gun and the serial number would help. Maybe someone else can help.
Welcome to the forum. If the K precedes the serial number yours is roughly a late 1951 or early 1952 manufacture. I have a 1951 K-38 less than 1,000 away from your serial number so it should look a lot like this one.
Welcome from Pennsylvania, USA. The placement of the letter "K" is confusing me. Please double check that and provide us with some pictures.
We really like pictures here.