Its my limited understanding that GI bill itself didn't exclude black veterans, but its administration was conducted at the local level where many of them faced an impossible uphill battle. After the civil rights movement won some victories, was there ever a serious push to reopen old applications or the window to apply to veterans or their families?
Not exactly an answer but did the FHA and Civil Rights act sort of address this in the supply end?
My understanding is that VA home loans went to private single family homes in Levittown type developments, so those bills sort of addressed the local level institions that prevented the role of the government in illegally forcing African Americans and other minorities into affluent neighborhoods because of federal subsidy.
http://www.civilrights.org/resources/civilrights101/housing.html
Timing wise these bills were in years like 1968 in the case of the FHA, so it sort of had some of the effects you suggested without the explicitness.
This next source has some info on the expansion of the program in parallel with the wars the United States was involved in during the last century.
http://www.benefits.va.gov/homeloans/docs/history.pdf
Your question is sort of narrow in that it erases Korea/Vietnam. My understanding of the source is that mortgages had to be originated within something like 5-10 years of the end of WWII (this was later exapnded to 1967 at the latest for wwii vets) so there would have been little to do to rectify the situation withoht redoing the program or a bunch of ex post facto changes. Even the expanded bill for elligibility only pushed it back to a little bit prior to the passing of the Fair Housing Act.
Minorities also historically (and still do) have lower credit ratings for a variety of reasons (discrimination/employment discrimination/intergenerational wealth), so on the macroeconomic level they likely qualified for less per applicant, as well as a lower number of approved veterans per applicant in comparison to Caucasian Americans .
Essentially irrespective of the hypothetical quality of the borrower, the WWII class of military beneficiaries had already aged out of VA mortgages.
They would have had more grounds to sue for discrimination with the FHA and evolving legal opinions with "disparate impact" becoming a doctrine of evidence of discrimination, which is much easier to prove than de facto discrimination .
The FHA program was underutilized in the 1960s even with lots of Veterans and 14 million not using it at all, so the alleged need or harm done by the siuation would be interesting to see empirical data on.
Likewise, the evidence needed to prove these cases would have been etherial at best .If someone shuffled a minority bid on a house to the bottom of the pile likely would have been trashed after the sale went through. And what would the remedies have been? A case against the former owner? A case against the current owner? A case against the loan officer?
From a legal history perspective, they could have likely had grounds under the "equal protections under the law" clause in the Constitution even without the FHA if they faced discrimination by the local administrative boards that approved GI benefits, but I'm unaware of any cases that argued this .