Yes.
SciTE is one thing, mostly independent of the complementary functions created on it for AutoIt.
So you can have an older SciTE version running a functional AutoIt v3.x.x.x without (much) problems.
So much so, that I have portable versions of AutoIt : v3.2.0.1, v3.2.12.1, v3.3.6.1, v3.3.8.1, v3.3.14.2, v3.3.14.5 running currentish SciTE.
You should be able to run your setup, without necessarily having to have a full SciTE setup but just the components you actually use.
Then again, it's your project, you decide what you understand to be better, under your experience and current needs