Keeler locks are rectangular and are taller than they are wide. If your lock is wider than it is tall, this is not the correct cylinder.
The cylinder is approximately 1.25" from the face to the back tip of the cylinder. However, the actual look of the cylinder will vary.
The cylinder comes with 2 keys.
We've discovered that this lock was also used on late 1970s Fleetwing trailers. Do you know another make of trailer that used this lock?