I may be making a few big assumptions here, but here's my take:
All Stellas use the same front brake pad.
Looking into parts vendors in the UK by searching for LML Star brake rotor, I learned three things.
1) The rotor has a 96mm bolt pattern.
2) The rotor mounts to the hub with 5 bolts.
3) There is a list of bikes that use this rotor, which follows.
GILERA DNA 50
LML STAR 125 2 STROKE
LML STAR 125 4 STROKE
LML STAR 150 4 STROKE
PIAGGIO HEXAGON LX 125
PIAGGIO HEXAGON LX 180
PIAGGIO SFERA 125 RST
PIAGGIO SFERA 50 RST with DISC FRONT BRAKE
PIAGGIO ZIP 125
PIAGGIO ZIP SP 50 1996>1999
PIAGGIO ZIP SP 50 2001 ON
VESPA ET2 50
VESPA ET4 50
VESPA ET4 125 1996>2000
VESPA ET4 125 2000 on
VESPA LX 50 2 STROKE and LXV 50 2 STROKE
VESPA LX 50 4 STROKE
VESPA LX 125 and LXV 125
VESPA PX 200 E DISC
VESPA S 50 2 STROKE
VESPA S 125
Interesting that the Vespa ET-series and LX-series uses the same rotor. The important bit is that the rotor is the same for the 2T and 4T model. Makes sense, since the pads are the same.
The only unknown at this point is the size of the axle spindle. Way back in days of yore (I think it was in the latter half of the '80s?), Piaggio changed the front axle size from 16mm to 20mm on the P/PX series scooters (from which the Stella came about). I believe that the disc-brake bikes all had the 20mm axle and it would make sense if the Stella did too.
I found a link for a
front hub from SIP for retrofitting on PX-Vespas with the "star" hub. Doesn't look modified to me, though. Only modification I could imagine is sleeving it down to fit the older, 16mm axle.
If I was a betting man, I'd say that the hub off of any 2T Stella is a bolt-on for the 4T models and most likely, the Automatic variant too. I have access to a spare hub so I will be trying the swap once I've gotten my 4T. I'm also betting that if ScooterWorks swapped it on, it was probably a direct swap. If fiddling had been required, the blog post would have mentioned it.
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...
Seriously...I've lost count...
Seven mopeds ...that's still manageable...