Yes, that's correct. In the early years, they sold many that were P25 capable........just add the expensive UT-120 module & purchase the expensive software key to activate the module. I purchased one off eBay that was advertised as P25 compliant. After countless hours trying to get it working with P25, I finally called ICOM in Washington state. Gave the tech guys the s/n and they told me it didn't have the module or the key. With a little nudge from PP, I got my money refunded.
The F70DT-11 is the least expensive version that has P25 out of the box. The -31 has a whole bunch of bells & whistles that you probably will never use (unless you're a first responder) and they drive up the price considerably.
Bob
N2OAM