Why not? If you're not happy then go to another garage for a second opinion. A starter motor is not KTM specific, any garage can tell you. Or buy a cheap battery charger and test yourself. The markup on a starter motor probably won't make much difference to his yearly bottom line...
Regards
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KTM LC4 640 Adventure-R 2001
Previous bikes...
KTM Duke II 2000
Kawazaki ZX-6R 1998
BMW F650 1996
+ others...
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