Good question...I will look for the information.
It may not say that specifically, but it will give an 'Insulation Class", which is what tells you what you need to know to start with.
140F = 60C. Base temperature is 40C, so at 60C ambient you have already consumed another 20C of rise capability. What you don't know here however will be the rise you are currently expressing on the motor now. Your motor will be raising the temperature of the windings at those slow speeds because of a drop in cooling effects, harmonics in the VFD output etc. That will likely remain the same when you move it, so if you can find out what that is, it will tell you whether or not the move is safe.
Example: lets say your motor is currently in a 40C environment (102F) and you have Class F insulation (very common). But let's say the application is raising the internal winding temperature to 145C, that is a 105C rise over ambient. Class F insulation is 40C ambient base, + 105C rise means it's fine for up to 155C, you are at 145C, so no problem now. But if you move that motor to a 60C environment, then the rise is still 105C over ambient, now you are at 165C so you are exceeding the maximum allowable temperature of the insulation. There is a "hot spot" allowance of 10C (shown as "Thermal Margin" in that chart), but you can expect a shorter motor insulation life now. The "rule of thumb" on that is that for every 10 degrees C rise over maximum, you cut the motor insulation life by 1/2.
Same scenario, but Class H insulation, no problem.
The difficulty is, you may not know what the INTERNAL winding temperature is right now, unless you have performed a Resistance Temperature Test or have some sort of temperature sensor inside. IR scanning from the outside is not a good indicator of the internal temperature, but one thing it can tell you is a MINIMUM temperature. In other words if your IR scanner sees that the case it 105C now, it's a sure bet that your winding temp is AT LEAST 105C now. It's likely 20-30C higher though.
If you do not have internal sensors, the only way to determine the motor internal winding temperature is to do the Resistance Temperature Test, which measures subtle differences in motor winding resistance between cold and hot to calculate the temperature rise. If you look at this link, it provides a decent description of the procedure, about 3/4 of the way down the page.
http://www.leeson.com/TechnicalInformation/hottopic.html