Seimitsu's "SS P=40" mounting plate is best used for wooden cases or cases that have a thick top panel and must be mounted to its underside.
The P-40 covers mounting points of the LS-58-01, LS-56-01 (as used to mount LS-56-01 in HRAP 3), and posesses the same screw mount positions utilized by the Sanwa JLF TP-1.
~Much thanks to SRK's George C for the information.