Because of the episode where Goku and Vegeta train in another dimension we know god ki can be transparent. And in the Fukkatsu no F movie / anime saga, Goku is able to fight Freezer 4th form in "base" form, and Vegeta is able to deflect a ki blast from golden Freezer also in "base" form. Were they using god ki in this base form (what would make them to have a strenght close to a super saiyan god) or were those form their regular base form?
There isn't really an exact answer to this question. This is because, it was implied early on in the series that Goku had supposedly absorbed this God form into his base form and some might argue whether this is true or not. The only thing we know for a fact is that Goku and Vegeta grew way stronger.
However, based on Whis's definition of God Ki, it is basically being able to power up without having ki leak out of your body. Goku and Vegeta were both being trained to master this skill and the Super Saiyan Blue transformation, is basically them blending the Super Saiyan transformation with God Ki. So while mastering this power, Goku and Vegeta grew immensely powerful in their base forms, which is why we see Goku being able to easily fight Final form Freiza and overwhelm him. We also, later on, see Vegeta(Copy Vegeta) being able to easily defeat SSJ3 Gotenks without any struggle. So in a way, they were probably utilizing God ki but the two of them had become immensely stronger since the Buu Saga.
The Tournament of Power took place a long time after Fukkatsu No F(Return of Frieza). So it is safe to assume that TOP Base form Goku is stronger than ROF Base Form Goku.
Now, in the tournament of power, Goku used all of his transformations but the only time the spectators (Hakaishins, Kaioshins, Angels and other fighters) were aware of god-ki being used was when Goku fought in SSG/SSB form. So, to answer your question :
Did Goku and Vegeta have God Ki while fighting Freeza in Fukkatsu No F? Yes.
Were they using it in their base form against Freeza? Maybe. But others won't be aware if they are using God-ki in base form as seen from the Tournament of Power arc.