GPS or not ?

[lesept]

My HTC Diamond was given to me by my employer, and the GPS seems not to be in it. It has a custom ROM from Orange, french phone company.
I'm wondering if the GPS is in it or not, because I don't think that, at HTC, they would make phones with GPS inside, and others without (it seems too expensive). But they could lock it by software.

So my question is : if I change the ROM to the original HTC one, would I by any chance get the GPS working ? What do you think ?