SMC shaft vs. EAI shaft

I'd like to know if anyone knows if the SMC 300- 3.25x5 has the same shaft diameter and threads as the blue/ silver EAI- 3.5x 5 shaft? I'm trying to replace my EAI with SMC but would like to use the same lower brackets. The lower brackets I use now are the screw on types for an Eclipse.

I want to order these tomorrow (Mon.) but the rep at MIC didnt help much. Said he don't know the shaft diameter or thread. I mean I would have already ordered them if the rep had the specs I asked for.