Dearborn disc harrow

I picked up what I believe is a dearborn Disc Harrow Series D Or at least it looks like one, see photos.
Can't read the tag
Looking at the brochure for the "D" in the manual section under specs I see they made a 6' and 7' disc. What has me puzzled is this disc is a 5'. Did they also make a 5'?

Follow Ups:

• Re: Dearborn disc harrow (url) - Tim Daley(MI) 07:06:16 06/09/18 (1)
  • Re: Dearborn disc harrow - Kirk-NJ 03:12:47 06/10/18 (0)

Name   : 
E-Mail : 
Subject: 

Message:

To add a single image to your post,  click here.
To add multiple images to your post, click here.

Optional Link URL : ←http://www.yourwebsite.com
Link Title        : ←Website Title
Optional Image URL: ←http://www.myimages.com/mypic.jpg

Enter image characters into the text box.

Press Preview Message button below to proofread message & check if images and/or links are shown before posting message. Press browser's back button if correction is needed. Press Post Message button on Preview Message page to finalized your post. Thanks!