Ok, I may have been mistaken on the problem fit. I was basing my opinion on what I could feel from reaching up into the frame rail from below. With the cab tilted, I can now see that there are two bolts which hold the rubber stop in place. It's possible that the MFFFG mounting plate will fit in one of those bolt holes and another bolt hole holding the motor mount to the frame. However, after my conversation with Ed Sanders, I'm thinking that simply mounting the rubber part thru one of the existing rubber stop mounting holes is actually a better option. I'm not looking for more load carrying capacity in the front like the people running snow plows, I'm looking for a less harsh bump stop.
I'll update once I get the chance to install.
If indeed the mounting plate needs to be installed, I'm hoping the nut on the motor mount plate is welded to the inside of the frame rail because I don't see any way of accessing it with a wrench.