Is your unit lime green in color? The last that one that I saw or worked on was a 72", lime green unit equipped with a Kubota diesel and that was in the late 80's or early 90's. At that time there was word that they were going out of business. They were a well built, heavy duty zero turn.
It's possible that they may have been bought out by Landpride which is a division of GreatPlains Manufacturing.
Are you able to find the model and serial number plate or decal on the unit? If so, you may be able to find some info at the following link.
That's about all I can come up with without a little more research or a phone call.