Extensole Corp. , Sparta , Michigan .
It prob. has "Watertown Slides" - Watertown , Wisc. slides on it .
You can check the slide mechanism for a patent # .
Go to uspto.gov , look on the L side of the page & select :patents , then > search patents .
It'll give you a rough idea of the date of your hardware .
A picture posted here will prob get you a quicker answer from the folks here , though ...