Storm door locking interior handle

I have a customer that has a Cole Sewell storm door that they believe was installed in the seventies. The registration number is 08259990321. 0036. Being so old it has worn out and they would like to replace it with an exact replacement or if need be something that would retrofit. I have the dimensions if you need them but at this time I am just including the picture of the part in question. Thank You - John L Neal.

Now that I am back in my office I have the dimensions of the interior handle/lock assembly that I can provide you. The overall length of the assy. is approx. 3-5/8"x 1-1/16 wide. From the top screw hole to the middle one is approx. 1-3/4", from the top screw hole to the bottom one it is approx. 3-3/16". The locking assy. just has a lever that slides the locking device into the receiving door jamb fitting.

Thank You Tom.