The Surgeon has an integral scope base which is a major selling factor for me.
PGW produced both the TWOLF and COYOTE initially with integral rails however Military clients specified removable rails as the fixed was deemed to not offer the flexibility required to facilitate various day/night sight configurations.
The rail is affixed with five 10-32 screws and a guide rib....if it comes off something serious enough has happened that you would not be concerned with the condition of the rifle.
As a side note I know Preston from Surgeon and he is a great guy with a great product. He can't party worth a damn and he is old but we don't hold that against him