Reporting question for Reverb Tank - MOD®, 4BB3C1D, Long Decay, 2-Spring

Product:
Reverb Tank - MOD®, 4BB3C1D, Long Decay, 2-Spring

Question:
What (really) is the difference between this one (4BB3C1D) and the 4BB3C1B? They appear to be identical except the for B vs. D (which describes the mounting as "vertical. connectors mounted down"...which is not how it's pictured. They are the same, yes?