No it doesn’t come with a BCG
Yes LH stands for left handed
The Stag Arms AR-15 Retro Right Hand Upper Receiver does not come with a full auto BCG or any BCG.
The Stag Arms Stag 15L Retro Upper, 20in, .223/5.56mm NATO, handguards do not have a mounting surface or rail. So you could not attach a Magpul Foregrip to it.
The Stag Arms Stag 15L Retro Upper, 20in, .223/5.56mm NATO model number STAG15111011, is the left handed model.
The manufacturer doesn't state if the Stag Arms Stag 15L Retro Upper Receiver has T Marks. I recommend contacting Stag Arms in regards to that information.
This Stag Arms Stag 15 Retro Upper is classified as an HBAR however the description is wrong regarding the twist rate. This barrel is in fact a 1-7 twist, not 1-8 and is in the process of being corrected on the product page.
The manufacturer classifies this Stag Arms Stag 15 Retro Upper as an HBAR rifle or "heavy barrel". However, I would contact the manufacturer and local authorities regarding the local laws regarding this upper receiver.
There is not one. No BCG or charging handle are included.
Rear Sight: Removable A3 Carry Handle with Integrated Sight.