Various Gearboxes have been used in the Lotus Elise and often they are not possible to identify from the exterior as the housing appears the same.

This said there should be a serial number on the unit, if this can be located they can be identified by this number as follows

GEARBOX SERIAL NUMBERS:

C6BP... - Standard box for Elise Mk1 and MGF

C4BP... - MGF VVC box (as standard but final drive 4.2)

B4BP... - Lotus CR box, Elise Mk1 111s + Elise Mk2 standard box

B4BPU... - Exige S1 (uprated)

B4BPQ... - Exige S1 with LSD

G6BP... - Elise S2 111S

Other sources of information

Rover PG1 gearbox