Question about the Duometre Chrono

Hi Looking to add a "high end" chrono and came across the duometre.

Stuck between a second hand model or purchasing new.
Close friend is parting with it needing the money.
He purchased it in 2013 with a model#q6012521.
the current model offerred by JLC is #q6012421.
Does anyone know the difference. Any thoughts on which route to go. the price difference is 25%
Thanks