It is stamped with 28C and is channel is 29" long. The window weighs 20 lbs.
Thanks for any help you can provide. Tom

Thanks for posting, Tom. Are you sure it's only 7/8"? We do not have a shoe with that kind of depth. It's possible that yours is the 15-005, and has just been worn down. Please double check the depth and make sure its as accurate as possible. Make sure that you're measuring the right part of the shoe. You can see what the depth is for the 15-005 below.