I think W&M made working man's rods, relatively inexpensive and pretty fair fishing tools, with not much glamour or superlative advertising copy.
I'm not an expert on these, but my thoughts are that the various models were on the same tapers/blanks but at different "trim" levels, some having very few guides and some having more than enough guides and some variation in wraps with different price points. As I recall the Champion was a mid range designation and the name may have been in use on several versions/generations of rods, possibly also casting rods. I've never seen the number designations explained but think they were trim levels with higher numbers being lower price ranges fe Sweetheart= 2A, Champion= 3A and Denco= 8A (maybe the fly rods use A and the spinning rods use B)
Reel seat colors and styles changed some through the years and could aide in dating, and I think the rods went through color changes that could date them too, though I'm not knowledgeable enough to say when what was changed.
I really like my ~'70 Denco and really dislike my ~'90 Sweetheart, but I put that down to USA vs Asia manufacture and brown vs yellow color, with the brown Denco being made in USA.
I guess that if the rod is marked "Eagle Claw" rather than "Wright & McGill" that it is more recent vintage