The standard long cover was fitted to the X8E2 unit optic sighted rifles
The half stripper clip loading cover was fitted to the X8E1 rifles.
The X8E3 was an X8E1 fitted fitted with the American designed 5 slot flash eliminator (often referred to the the 'Browning Flash Hider' on the 'G Series FAL rifles)
The X8E4, unknown but probably an X8E2 fitted with the Flash Eliminator
The X8E5 was a modified X8E1 with newly designed components such as a new version of Auxiliary Catch on the Cocking handle slide, new sling swivels, new butt plate and semi auto etc
The X8E6, unknown but probably an X8E2 fitted with X8E5 components