This is likely correct. Here's the instruction step that you mentioned:
In order to keep costs lower, TLG tries to limit the number of unique elements in a set and in an individual bag within a set.
The part you mentioned could have been a 1x1 system brick, but using a Technic brick here also works fine. Bag 9, the bag used for this step, already includes 1x1 Technic bricks as they are needed for subsequent steps, such as 265:
None of the other steps related to bag 9 use a 1x1 System brick. It is likely that the 1x1 Technic brick was used in step 264 in order to avoid having to include another element in this bag.