Good news, everyone!!! I spent quite some time looking for the original 70s 20th Century Fox logo present in the original SW in HD and today, I got the original MASH movie on Blu and found out that it's there, so I'll be able to use it :-)
I already had the 80s Fox logo used in Jedi in HD from the D-Box Alien DC, so now I'll be able to use an actual HD Fox logo in SW as well.