I dont think that's accurate. I think what @troyan said was actually right - DLSS 2, 3 and 3.5 are feature levels for a given game/app.DLSS3 is the Frame Gen feature...
DLSS3.5 is the Ray Reconstruction feature...
DLSS 2 means the game/app has SR only
DLSS 3 means SR+FG
DLSS 3.5 means all three
From Nvidia themselves:
Then again, what if a game would support RR but not FG...