No, it doesn't look like what we old folks think of when we think of a 520. That's just the Model that Ertl put on it.
That casting was used to represent 4430, 4440 and 4450...only differences were in the decal on the side of the hood.
The industrial yellow version was made for a couple of years, starting in 1990, I think.
New in Box price is around $700. Of course, that's only if you're trying to buy...when you're trying to sell, the price is always lower.
I have some scanned pictures of the ag version showing the decal differences....can e-mail them if you're interested.