Yes they are 7.5”. I am not worried about it 1 since I don’t air way down and I don’t worry about popping the bead off, 2 even Firestone says 7.5” is the narrowest wheel and 3 I may go with a weld on bead lock and won’t ever have to worry about it.
I would run a 7.5” with 315’s.
The FJ Cruiser wheel is narrower than stock and has more backspace than stock. The net result is you have narrowed your track by by almost 1 3/4 inches. The references I find list a minimum rim width for this tire to be 8.5 inches. You will be fitting a tire with a 10.2 inch tread width on a wheel with a flange-to-flange width of 8.5 inches. You will have quite a crown in that tread unless you really drop the air pressure. Your call.
will kill me if only one of the seats has seat heat haha.
About halfway through some maintenance this weekend (new gaskets, ignition, etc.). The more knowledge I have the better.