22 years ago as I was finishing the restoration of my 1958 TR3A, I re-set the voltage regulator. In its previous life (80,300 miles), it had been adjusted too high and it was spitting acid out the vents in the caps from 1958 to 1972 while I stored the TR till 1987. Needless to say, I had to change the battery box (amongst lots of other things).
With the regulator set to the correct output specifications, I have never had any need for a black AMCO battery box. The various batteries I have had during the 109,000 miles since 1990 have not spit, although for a while I had fabricated a removable cover over the battery and used it just in case. But I never needed it and removed it about 7 years ago, just before this photo taken in 2007. It still looks the same today.
Under the battery are the 4 original black rubber pads stacked 2 high on each side of the drain hole under the battery.
BTW, that's one of Frank's brass number tags you see. With the black AMCO battery box, you can't see the brass tag because it's hidden behind the top flange of the AMCO box.