The last regulator I bought for my 56 was also blue. All I did was paint it black and added a decal to the top which had all the correct numbers.
If your regulator is working ok, just do what I did.
I have had my 56 for 6 years. never had an electrical problem other than a regulator that went sour on me (no telling how old it was as it was on the car when I bought it). Unless your running air, a generator works fine. I have had more problems with alternators than with generators. On another car I have that was previously converted to an alternator, I went through three of them before I got one that worked properly.
Midland Park, NJ
56 TBird, 54 Ford, 48 Ford, 64 Fairlane