Yes this is correct. In many videos online the WT mats seem to sag. I didn't go with them for this reason.
I have the 3DMAXpider front and back seat floor mats, and although they were advertised as being for the April 2021 refresh Model Y seats in the front, there is still a gap of an inch or two between the back end of the mat, and the point where the front seats attach to the floor, and I will probably be sending them back.
I have ordered an entire set (frunk/trunk/storage areas etc )of ToughPRO (Made in USA) floor mats for $140 on Amazon. My buddies who have Teslas, except for one, said get these in the first place. The one outlier has 3DMAXpiders in his 2020 M3.