1970s 75-78 Eldo hubcap colors?

[TJ Hopland]

What was the deal with the color of the Eldo hubcaps?  75 was the first year for that style or was 74?   And 75 was no color, 76 was black? except for bicentennial? and 77-78 was body color?

What raised the question is a 76 just popped up near me that is supposedly a very low mile original car and I think it looks terrible with the black caps and light blue paint.  Or is one of those colors not correct for 76 and this car has had something go wrong at some point in its not driven life?   I'm not interested in buying it or anything just curious.

[Eric DeVirgilis CLC# 8621]

1974-1975:

Identical style -  brushed stainless steel only.

1976:  Painted as below:

Standard - Black.
Bicentennial (conv) - White
Eldorado Custom Biarritz -  matched to body color in the five colors available on Biarritz: White, Black, Firethorn, Academy Gray, Innsbruck Blue.

1977-1978:

When equipped with Cabriolet Vinyl Roof: Butyrate insert (not painted) matched in every body color.
When equipped with full vinyl roof or steel painted roof: Unpainted brushed stainless center hub. 

[TJ Hopland]

I don't know that I have ever noticed black before except maybe on a black car so I wonder if owners were maybe like me and didn't like the look with many body colors and changed them?

[Eric DeVirgilis CLC# 8621]

Every so often, I come across 1976 Cadillac wheel covers with center hubs painted to match body color. Normally this was done with the optional turbine vaned covers available on Calais/DeVille; standard on Brougham d'Elegance/Talisman in which the center hubs were also painted black originally. If you Google images for "1976 Eldorado", the vast majority of cars have black covers except for the sub-models listed above.

Incidentally, the outer ring on the 77-78 Eldorado covers with butyrate insert didn't receive color. Only the '76 Eldorado (painted) covers had color in this area.