exop, since none of the Buckeye "experts" have chimed in on this question I'll take a crack at it.
Buckeye eye color changes with age and most will be a reddish orange....leaning more toward the "orange" side when the bird is fully mature (20-22 weeks of age).
They will start out pale yellow or light gold or "greenish gold" as you put it but ALL of mine end up with the "orange/red" as the mature.
Oddly enough the original APA standard from 1904/1905 states the Buckeye should have RED eye color but I've never seen one that I would call a true "red"!
By the way, I'm the owner of Crains Run Ranch and I have the following lines in my breeding pens;
ALBC (Urch/Pearce/Rhodes/Brown)
Brown (Urch/?/?)
Fitche or Fitch (pick your spelling)
Pearce (Urch)
Pierce (Fitche)
Rhodes (?)
Urch (Tallman)
Basically, ALL of these lines are Urch related somewhere along the line except perhaps the Rhodes & possibly the Fitche lines.....I'm sure this will stir some debate but the truth is Mr. Urch has had the longest running line that dates back to the 1950's and nearly EVERY Buckeye breeder has used a Buckeye or two from Mr. Urch at one time or another! Unless a breeder crosses another breed with their Buckeye stock the eye color should NOT vary in these strains but I suspect over the year some breeders have done just that. At least one of these breeders admitted he crossed Dark Cornish and RIR blood at one time or another so I suspect others have done the same but just haven't been so forth coming with their cross breeding "projects".
Yes, the "Fitche" line does exist and from my research it may contain the original "Romig" (of Maine, not New York) blood or vice versa, this is still a bit unclear depending on whom you ask. There are a few folks who own "Pearce" Buckeyes and another line of "Pierce" that are often confused with one another. One came from the west coast (Dennis Pearce) and the later (Ron Pierce) came from the east cost. The Pearce line originated from Urch but the other Pierce line came from Fitche's line 18 years removed!
The "newer" lines you have mentioned, mine included, are a combination of 2 or more lines and for the most part one might argue they are a variation on the ALBC line. According to Don Schrider the ALBC line was heavy on the Urch/Pearce but had a little Brown and even less Rhodes influence....in Don's words they developed a "true Urch" line by crossing current Urch to old Urch (Pearce line).
Now I'm rambling but my point with ALL of this comes back to the Buckeye eye color question....all these lines that I own have the same eye color and it's more reddish orange than "bay" or "reddish bay"!
Hope this helps,