carpet and rear seat question

[68 CHARGER R/T]

trimming the carpets fellas when it comes to the rear of the car does the carpet run behind the quarter panel trim ,   it's been years i just cant remember.also i was putting my rear seat back in yesterday and the two tabs  that are attached on the wheel well on the car are off for some reason , the passenger side one is lower about an inch from the drivers side is this normal cause i cant get the passengers side to lock in place so the so that side doesnt pop up the seat   

[twodko]

When the upholstery shop did my 69 they did tuck a bit of carpet up under the door panels.....about 1/2" or so.
As far as the seat tab goes:

Can you bend it up a bit to engage?

If not perhap you could rivet an extension piece of sheet metal so it will engage. 

[68 CHARGER R/T]

so under the quarter  panel trim  it goes ,  the tab i cant make it to bend upwards         thanks anyways   twodko