No Screws To Drill Out
I'm afraid that the latch I see in your photos is no longer available. I believe it was discontinued. However, you may be able to use our 91-054 as a substitute. You will need to check it out to see if our dimensions match up to yours.
As for taking your storm sash apart, In some cases there could be a screw at the corner of the frame holding it together. In other cases your frame could be pinned at the corners. You will need to look closely at the corners of your frame to see how it is held together. Look at the related videos on taking frame apart to see if this is the type you have. If you aren't sure, take it to a hardware store or a glass shop in your area to see if they can help with the repair.