I was able to remove the drilled cylinders from my last post ( https://www.reddit.com/r/Locksmith/comments/j12m7n/removing_cylinders_from_security_door_after_it/ ), thank you for the suggestions, they were very helpful.
The entire lock body is aged/destroyed and now needs to be replaced. I have spent at least five hours trying to search for a replacement, but can’t find one with the exact same measurements.
They are ALMOST exactly the same as this Marks mortise lock: https://cdn11.bigcommerce.com/s-oxb3wyri4w/images/stencil/480×420/products/2406/12374/MARKS_ORNAMENT_IRON_DIMENSION_copy__22423.1551724762.jpg?c=2
The only difference is the position of the cylinder. In the above diagram, the distance from the top of the faceplate to the center of the cylinder is listed as 1-7/8″, while mine is 1.5″.
I am at my wit’s end trying to find a replacement. I have found many possibilities that have a 2.5″ backset and a 7-1/8″ faceplate height, but the cylinder position is either too low, like the Marks set, or much more commonly, that measurement is unlisted in the diagram.
Here is a picture of the lock body: http://imgur.com/gallery/zXqMcOq
I couldn’t find any identifying brand marks on it, or the iron gate-type door. They were probably installed when the house was originally built in the early 70’s, in Denver, Colorado.
Any help identifying the model, a potential replacement, or a place to look for one, would be GREATLY appreciated. Thank you for your time.