Good question. I'd imagine the only thing that maybe different are the springs for the primary. Outside that the thread sizes should be the same.
I couldn't find anything on the Bob's Knob site.
If your planning to get the 16" LB just confirm with the dealer, I think Meade may have changed the primary screws so that you don't need to get aftermarket ones anymore.
Cheers, Norm
PS: when i say springs are different, they may just take heavier mirrors.